Yoshida, Mitsunobu (Sodegaura, JP)
Watanabe, Hiroshi (Sodegaura, JP)
Ono, Takashi (Sodegaura, JP)
Nogi, Hidenobu (Sodegaura, JP)
Nakata, Tomoyuki (Sodegaura, JP)
Plaque It!
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Translation JA 2001-319807.
Official Action issued by the Japanese Patent Office on Jul. 11, 2006 in corres. JP Appln. No. 2002-276333, and English translation thereof.
Official Action issued by the Japanese Patent Office on Jul. 11, 2006 in JP Appln. No. 2002-276333, and English translation thereof.
Official Action issued by the Japanese Patent Office on Aug. 22, 2006 in JP Appln. No. 2002-254394.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of PCT/JP03/00290 filed on Jan. 15, 2003, which claims the benefit of Japanese Patent Application No. 2002-7023 filed on Jan. 16, 2002, Japanese Patent Application No. 2002-17609 filed on Jan. 25, 2002, Japanese Patent Application No. 2002-89931 filed on Mar. 27, 2002, and Japanese Patent Application No. 2002-111018 filed on Apr. 12, 2002, the contents of which are incorporated by reference.
1. A magnetic substrate comprising a heat resistant resin and/or a precursor thereof applied on at least a part of a side or on at least a part of both sides of an amorphous metal ribbon represented by the general formula:
(Co(1−c)Fec)100−a−bXaYb wherein X represents at least one species of element selected from the group consisting of Si, B, C and Ge, Y represents at least one species of element selected from the group consisting of Zr, Nb, Ti, Hf, Ta, W, Cr, Mo, V, Ni, P, Al, Pt, Rh, Ru, Sn, Sb, Cu, Mn and rare earth elements, c, a and b respectively satisfy 0≦c≦1.0, 10<a≦35 and 0≦b≦30, and a and b are represented in terms of atomic %; and the heat resistant resin comprises a resin that satisfies the following characteristics: (1) the weight loss rate owing to the thermal decomposition in a thermal history of 2 hr in a nitrogen atmosphere at 350° C. is 1% by weight or less; (2) the tensile strength after a thermal history of 2 hr in a nitrogen atmosphere at 350° C. is 30 MPa or more; (3) the glass transition temperature is from 120° C. to 250° C. (4) the temperature at which the melt viscosity is 1,000 Pa·s or less is not lower than 250° C. and not higher than 400° C.; and (5) the heat of fusion owning to crystals in the resin, which has been cooled from 400° C. to 120° C. at a rate of 0.5° C./min is 10 J/g or less.
2. The magnetic substrate of claim 1, wherein c in the said general formula satisfies:
0≦c≦0.2.
3. The magnetic substrate of claim 1, wherein the heat resistant resin comprising a resin that satisfies the following characteristic: (5) the heat of fusion owning to crystals in the resin, which has been cooled from 400° C. to 120° C. at a rate of 0.5° C./min is 10 J/g or less.
4. The magnetic substrate of claim 2, wherein the heat resistant resin comprising a resin that satisfies the following characteristic: (5) the heat of fusion owning to crystals in the resin, which has been cooled from 400° C. to 120° C. at a rate of 0.5° C./min is 10 J/g or less.
5. The magnetic substrate of claim 1, wherein c in the said general formula satisfies:
0.3≦c≦1.0.
6. The magnetic substrate of claim 5, wherein the heat resistant resin comprising a resin that satisfies the following characteristic: (5) the heat of fusion owning to crystals in the resin, which has been cooled from 400° C. to 120° C. at a rate of 0.5° C./min is 10 J/g or less.
7. A laminate comprising the magnetic substrate of claim 1.
8. The laminate of claim 7, wherein c in the general formula satisfies 0≦c≦0.3, the laminate of amorphous metal ribbon has a relative magnetic permeability, p, of 12,000 or more and a core loss, Pc, of 12 W/kg or less, which are measured in a closed magnetic path at a frequency of 100 kHz, and a tensile strength of 30 MPa or more.
9. The laminate of claim 7, wherein the iron loss, maximum magnetic flux density and tensile strength satisfy the following requirements: (1) the iron loss W10/1000 is 15 W/kg or less; (2) the maximum magnetic flux density, Bs, is not less than 1.0 T and not more than 2.0 T; and (3) tensile strength is 500 MPa or more.
10. An applied magnetic part comprising the magnetic substrate and/or the laminate of magnetic substrates defined in claim 1.
11. An applied magnetic part comprising the magnetic substrate and/or the laminate of magnetic substrates defined in claim 2.
12. An applied magnetic part comprising the magnetic substrate and/or the laminate of magnetic substrates defined in claim 5.
13. The magnetic substrate of claim 3, wherein the heat resistant resin having a repeat unit represented by one of the following chemical formulae (15), (24) and (26) to (36)
14. The magnetic substrate of claim 4, wherein the heat resistant resin having a repeat unit represented by one of the following chemical formulae (15), (24) and (26) to (36)
15. The magnetic substrate of claim 6, wherein the heat resistant resin having a repeat unit represented by one of the following chemical formulae (15), (24) and (26) to (36)
TECHNICAL FIELD
The present invention relates to a magnetic substrate produced using a ribbon comprising an amorphous metal magnetic material and a heat resistant resin, a laminate of the substrate and a method for producing thereof. The present invention further relates to a member or a part of applied magnetic products using the magnetic substrate or the laminate.
DESCRIPTION OF RELATED ART
An amorphous metal ribbon is an amorphous solid produced by rapidly cooling the starting material that is selected from various types of metals from its molten state. The ribbon usually has a thickness of from about 0.01 mm to 0.1 mm. The amorphous metal ribbon has a random atomic structure that does not have regularity in the atomic ordering, thereby exhibiting excellent properties as a soft magnetic material.
In order to elicit its excellent magnetic properties, the amorphous metal ribbon is usually subjected to a heat treatment of predetermined conditions. Although the conditions for the heat treatment can vary depending on properties to be elicited and type of the amorphous metal, generally the treatment is conducted in an inert atmosphere at a high temperature such as from about 300 to 500° C. and for a long period of time such as from about 0.1 to 100 hr. While excellent magnetic properties are elicited by the heat treatment, the treatment makes the ribbon extremely brittle and makes its handling physically difficult.
As the electronics and communication industries grow significantly, the demands for applied magnetic products used in electric or electronic instruments rapidly grow thereby causing a rapid increase in the variety of the types of the products. Although the amorphous ribbons are planned to be used in various utilities because of their excellent magnetic properties, they are actually used only in such an application as a wound iron core, since the heat treatment, which makes the ribbon brittle, is necessary to improve the magnetic properties.
In order to solve the challenge described above, a method to laminate and adhere the amorphous metal ribbons, using as an adhesive, a heat resistant polymer compound such as a polyimide that resists the temperature at which the heat treatment for the purpose of improving the magnetic properties of the amorphous metal is proposed in Japanese Patent Laid-Open Publication No. 175654/1983. According to the method, the technical challenge of handling brittle ribbons is solved, because the adhesion and lamination using the heat resistant resin are accomplished simultaneously with the heat treatment. However the magnetic properties deteriorate in comparison with the case of not using the resin, because of unnecessary inner stresses caused by the heat resistant resin.
Recently, further higher efficiencies and higher performances (high magnetic permeability and miniaturization) are demanded in various electric or electronic parts and products that utilize magnetic materials. That causes a high demand for the higher magnetic properties (low loss, high magnetic permeability and high magnetic flux density) of the magnetic materials used in them.
A magnetic material that has excellent magnetic properties, which is potentially possessed by amorphous metal ribbon and mechanical strength has not been developed, and its development has been desired in view of the above-mentioned situation.
Conventionally, amorphous metal ribbons were used in a form of a laminate to achieve sufficient mechanical strength, and it necessitated the usage of an adhesive. The adhesive had to be heat resistant with regard to the heat treatment to improve the magnetic properties. For examples; Japanese Patent Laid-Open Publication No. 36336/1981 describes a method for producing a laminate in which an adhesive is coated on an amorphous ribbon to improve the punchability; Japanese Patent Laid-Open Publication No. 175654/1983 describes a method in which a heat resistant resin is coated on an amorphous metal ribbon previously and then a heat treatment to improve the magnetic properties is conducted in a magnetic field; and Japanese Patent Laid-Open Publication No. 45043/1988 describes a method in which ribbons are laminated with a resin that covers not more than 50% of the area to be adhered. In each of the described methods, neither a method of selecting an appropriate combination of a magnetic metal and a heat resistant resin nor a method for producing a laminate suitable for the combination is sufficiently described. Furthermore, the occurrence of delamination or fracture during the processing of the laminate after the lamination has not been completely prevented.
With respect to the application for an antenna using an amorphous metal ribbon, Japanese Patent Laid-Open Publication No. 233904/1985 describes an antenna apparatus using an amorphous magnetic core. Japanese Patent Laid-Open Publication No. 267922/1993 describes an automotive antenna used in a frequency range of from 10 kHz to 20 kHz. According to the publication, a core material obtained by laminating amorphous metal ribbons is subjected to a heat treatment at from 390° C. to 420° C. for about from 0.5 hr to 2 hr, then an epoxy resin or so is impregnated into it. Furthermore, Japanese Patent Laid-Open Publication No. 278763/1995 describes an antenna core obtained by laminating amorphous metal ribbons. In the publication, an antenna having a high Q value (Quality factor: Q=ωL/R; ω=2πf; f: frequency, L: inductance, R: resistance including estimated loss of coil), which represents performance as an antenna coil, at a frequency of 100 kHz or more is proposed. However, detailed explanations on an actual antenna are not described. According to the latter two of the publications, epoxy or silicone resin is impregnated in the core after the heat treatment for the purpose of improving the magnetic properties. Therefore, another heat treatment at a temperature of lower than 300° C., more specifically lower than 200° C., is necessary to harden the resin. It is inevitable that the magnetic properties deteriorate in comparison with those right after the first heat treatment.
In order to deal with the depletion of energy resources, electric motors and electric generators widely used in electronic instruments are demanded to be more highly efficient. Losses in electric motors or electric generators are caused mainly by iron loss, copper loss and mechanical loss. From the viewpoint of reducing eddy current loss, a magnetic thin plate having the smallest thickness as possible has been desired. In this respect, a silicon steel, a soft magnetic iron or a parmalloy is widely used these days. These poly-crystalline metals are cast to form ingots and then hot-worked and cold-worked to form a sheet of desired thickness. In case of using silicon steel, the thickness of the sheet is limited to about 0.1 mm or more owing to the brittleness of the material or so on.
Magnetic materials such as amorphous metal ribbons comprising Fe or Co as their main component are considered to be hopeful material for a magnetic core, which is a key part to improve the efficiency of an electric motor. However, as described above, the magnetic materials such as amorphous metal ribbons comprising Fe or Co as their main component require a heat treatment at a high temperature of from 200° C. to 500° C. to elicit the magnetic properties. The heat treatment makes the ribbons brittle, and when a stress is applied on the material, cracks or chips are generated. Therefore, it is difficult to obtain a laminate having the shape of electric motor core using the materials.
As a method for producing a laminate of amorphous metal ribbons used for an electric motor or an electric generator, Japanese Patent Laid-Open Publication No. 312604/1999 describes a method in which a laminate is produced using an amorphous metal as the ribbon and an epoxy resin, a bis-phenol A type epoxy resin, a partially saponificated montanic ester wax, a modified polyester resin, phenolic butyral resin or so on as the resin. However each of the resins is considered to have insufficient heat resistance at the heat treatment temperature of the magnetic core (from 200° C. to 500° C.). Therefore, the heat treatment, even if it is conducted after the lamination, makes the amorphous metal ribbons brittle, and stresses caused by loads applied during the lamination generate cracks or chips in the amorphous metal ribbons. These phenomena are considered to be problems in the practical use.
SUMMARY OF THE INVENTION
The inventors reviewed the composition of the known magnetic metals and reviewed the processes of lamination, adhesion and heat treatment. And, as a result of intensive researches, the inventors found out that it is possible to produce a material having desired mechanical properties and excellent magnetic properties, by using amorphous metal ribbons, using a substrate, wherein a heat resistant resin that resists the heat treatment in order to improve the magnetic properties of the magnetic material is applied, and by subjecting the materials to a treatment in a pressurized condition.
It was made clear that one can provide a substrate or a laminate, wherein a laminate prepared by heat-treating after stacking and adhering amorphous metal ribbons has a small deterioration in magnetic properties. It was also made clear that one can provide a magnetic core that has a high Q value, which is a performance index as the inductance of a laminate obtained by laminating amorphous magnetic ribbons, and has been stiffly unified by using the magnetic substrate.
As a result of an intensive research, the inventors have found out that in a magnetic substrate comprising a resin and an amorphous metal ribbon and a laminate of the substrate, when an amorphous metal ribbon having Fe or Co as its main component is used as the amorphous metal ribbon, by carrying out a laminate-adhesion between the resin and the amorphous metal or between the amorphous metal and the amorphous metal through the resin and a heat treatment for the purpose of improving the magnetic properties simultaneously in a specific condition, or by firstly carrying out a laminate-adhesion in a specific condition and secondly carrying out a heat treatment for the purpose of improving the magnetic properties in a specific condition, it is possible to provide a magnetic substrate comprising an amorphous metal ribbon and a heat resistant resin and having both excellent magnetic properties, which the amorphous metal ribbon having Fe or Co as its main component originally possessed, and intended mechanical properties and a laminate of the magnetic substrate, to complete the present invention.
The inventors have found out that, in a magnetic substrate comprising an amorphous metal ribbon containing more Fe than a specific amount and a heat resistant resin or a laminate of the magnetic substrates, a material having low iron loss and high tensile strength by carrying out a pressurized heat treatment can be obtained. The inventors have also found that the material is preferable for a stator or a rotor of an electric motor or an electric generator to complete the present invention.
In short, the present invention provides a magnetic substrate characterized by the fact that a heat resistant resin and/or a precursor thereof is applied on at least a part of a side or on at least a part of both sides of an amorphous metal ribbon represented by the general formula:
(Co (1−c) Fe c ) 100−a−b X a Y b
wherein X represents at least one species of element selected from the group consisting of Si, B, C and Ge, Y represents at least one species of element selected from the group consisting of Zr, Nb, Ti, Hf, Ta, W, Cr, Mo, V, Ni, P, Al, Pt, Rh, Ru, Sn, Sb, Cu, Mn and rare earth elements, c, a and b respectively satisfy 0≦c≦1.0, 10<a≦35 and 0≦b≦30, and a and b are represented in terms of atomic %.
The present invention also provides a magnetic substrate characterized by the fact that a heat resistant resin and/or a precursor thereof is applied on at least a part of a side or on at least a part of both sides of an amorphous metal ribbon represented by the general formula:
(Co (1−c) Fe c ) 100−a−b X a Y b
wherein X represents at least one species of element selected from the group consisting of Si, B, C and Ge, Y represents at least one species of element selected from the group consisting of Zr, Nb, Ti, Hf, Ta, W, Cr, Mo, V, Ni, P, Al, Pt, Rh, Ru, Sn, Sb, Cu, Mn and rare earth elements, c, a and b respectively satisfy 0≦c≦0.2, 10<a≦35 and 0≦b≦30, and a and b are represented in terms of atomic %.
The present invention further provides a laminate of the magnetic substrate, wherein the amorphous metal ribbons described above are laminated with a heat resistant resin and/or a precursor thereof.
In the laminate of magnetic substrates of the present invention, which is characterized by the fact that a heat resistant resin and/or a precursor thereof is applied on at least a part of a side or on at least a part of both sides of an amorphous metal ribbon represented by the general formula:
(Co (1−c) Fe c ) 100−a−b X a Y b
wherein X represents at least one species of element selected from the group consisting of Si, B, C and Ge, Y represents at least one species of element selected from the group consisting of Zr, Nb, Ti, Hf, Ta, W, Cr, Mo, V, Ni, P, Al, Pt, Rh, Ru, Sn, Sb, Cu, Mn and rare earth elements, c, a and b respectively satisfy 0≦c≦0.3, 10<a≦35 and 0≦b≦30, and a and b are represented in terms of atomic %, the laminate of amorphous metal ribbons has a relative magnetic permeability, p, of 12,000 or more and core loss Pc of 12 W/kg or less, which are measured in a closed magnetic path at a frequency of 100 kHz, and a tensile strength of 30 MPa or more.
In another aspect of the present invention, it provides a magnetic substrate characterized by the fact that a heat resistant resin and/or a precursor thereof is applied on at least a part of a side or on at least a part of both sides of an amorphous metal ribbon, wherein the heat resistant resin comprises a resin that satisfies the following five characteristics:
- (1) the weight loss rate owing to the thermal decomposition in a thermal history of 2 hr in a nitrogen atmosphere at 350° C., measured using a DTA-TG is 1% by weight or less;
- (2) the tensile strength after a thermal history of 2 hr in a nitrogen atmosphere at 350° C. is 30 MPa or more;
- (3) the glass transition temperature, measured using a DSC in a nitrogen flow at a heating rate of 10° C. per 1 mm is from 120° C. to 250° C.;
- (4) the temperature at which the melt viscosity, measured using a Koka-type flowtester, is 1,000 Pa·s or less is not lower than 250° C. and not higher than 400° C.; and
- (5) the heat of fusion owing to crystals in the resin, which has been cooled from 400° C. to 120° C. at a rate of 0.50° C./min, measured using a DSC in a nitrogen flow at a heating rate of 10° C. per 1 min is 10 J/g or less.
The heat resistant resin used in the present invention preferably is an aromatic polyimide resin that has one type or more types of repeating unit selected from the group consisting of those represented by the chemical formulae (1) to (4) in the main chain skeleton and having a ratio of aromatic rings having bonds in meta position to the total aromatic rings in the repeating unit is from 20 to 70 mol %.
In the formulae (1) to (4), each of X represents a bivalent bonding group selected from a group consisting of direct bond, ether bond, isopropylidene bond and carbonyl bond and can be the same or different; and each of R is a tetravalent bonding group selected from a group consisting of groups represented by chemical formulae (5) to (10) and can be the same or different.
Furthermore, the heat resistant resin preferably is an aromatic polyimide resin having a repeating unit represented by the chemical formula (11) or (12) in the main chain skeleton.
In the formulae (11) and (12), each R preferably is a tetravalent bonding group selected from the chemical formulae (5) to (10) and can be the same or different.
The heat resistant resin used in the present invention is preferably a resin comprising an aromatic polyimide resin having a repeating unit represented by the chemical formula (13) in the main chain skeleton.
In the formula (13) above, each of X represents a bivalent bonding group selected from the group consisting of direct bond, ether bond, isopropylidene bond and carbonyl bond and can be the same or different. In the formula (13), a and b are numbers that fulfill the relationships: a+b=1, 0<a<1 and 0<b<1.
As the heat resistant resin of the present invention, an aromatic polysulfone resin having one type or two or more types of repeating unit selected from the repeating units represented by the chemical formula (14) or (15) in the main chain skeleton is preferably used.
In another aspect of the present invention, it also provides a process for producing a magnetic substrate comprising an amorphous metal ribbon and a heat resistant resin characterized by the fact that the heat resistant resin is applied on the amorphous metal ribbon and then they are subjected to a heat treatment in a pressurized condition.
A process for producing a magnetic substrate of the present invention is characterized by the fact that an amorphous metal ribbon is subjected to a heat treatment in a pressurized condition.
In the process for producing a magnetic substrate of the present invention, the heat treatment is preferably carried out under an applied pressure of from 0.01 to 500 MPa and at a temperature of from 200 to 500° C.
The heat treatment in a pressurized condition can be carried out in more than one step and the conditions of the steps can be different from each other.
It is one of the preferred embodiments of the present invention to produce a magnetic laminate by carrying out a heat treatment under the conditions of an applied pressure of from 0.01 to 100 MPa, a temperature of from 350 to 480° C. and a time period of from 1 to 300 min after applying a resin on a side or on both sides of an amorphous metal ribbon represented by the general formula:
(Co (1−c) Fe c ) 100−a−b X a Y b
wherein X represents at least one species of element selected from the group consisting of Si, B, C and Ge, Y represents at least one species of element selected from the group consisting of Zr, Nb, Ti, Hf, Ta, W, Cr, Mo, V, Ni, P, Al, Pt, Rh, Ru, Sn, Sb, Cu, Mn and rare earth elements, c, a and b respectively satisfy 0≦c≦0.3, 10<a≦35 and 0≦b≦30, and a and b are represented in terms of atomic %.
It is also one of the preferred embodiments of the present invention to produce a magnetic laminate by applying a resin on a side or on both sides of the amorphous metal ribbons described above, stacking the ribbons and then subjecting them to the first heat treatment under the conditions of an applied pressure of from 0.01 to 500 MPa, a temperature of from 200 to 350° C. and a time period of from 1 to 300 min and subjecting them to a second heat treatment under the conditions of an applied pressure of from 0 to 100 MPa, a temperature of from 350 to 480° C. and a time period of from 1 to 300 min.
A method for producing a magnetic laminate comprising more than one magnetic substrate wherein a heat resistant resin layer or a precursor of the heat resistant resin is formed on a part or the whole area of a side or on both sides of an amorphous metal ribbon that is represented by a general formula:
(Co (1−c) Fe c ) 100−a−b X a Y b
wherein X represents at least one species of element selected from the group consisting of Si, B, C and Ge, Y represents at least one species of element selected from the group consisting of Zr, Nb, Ti, Hf, Ta, W, Cr, Mo, V, Ni, P, Al, Pt, Rh, Ru, Sn, Sb, Cu, Mn and rare earth elements, c, a and b respectively satisfy 0.3<c≦1.0, 10<a≦35 and 0≦b≦30, and a and b are represented in terms of atomic %, and obtained by a pressurized heat treatment under a press on an applied pressure at not less than 0.2 MPa and not more than 5 MPa at a temperature in the range of from 300° C. to 450° C. for 1 hr or more is one of the preferred embodiments of the present invention.
The laminate of magnetic substrates described above is preferably characterized by having the properties:
- (1) the iron loss, W10/1000, defined in JIS C2550 is 15 W/g or less;
- (2) the maximum magnetic flux density, Bs, is not less than 1.0 T and not more than 2.0 T; and
- (3) the tensile strength defined in JIS Z2241 is 500 MPa or more.
In producing the laminate of magnetic substrates of the present invention, a process characterized by putting a highly heat resistant resin sheet between a flat plate of a press and a magnetic laminate can be preferably utilized.
The magnetic substrate and the laminate thereof of the present invention can be used in applied magnetic parts.
A thin antenna, whose core comprises the magnetic substrate or the laminate thereof of the present invention, having coated conducting wire wound on the core characterized by having a insulating member on at least a part of the core on which the wire is wound is one of the preferred embodiments of the present invention.
Also, a thin antenna, whose core comprises the magnetic substrate or the laminate thereof of the present invention, having coated conducting wire wound on the core characterized by having a insulating member on at least a part of the core on which the wire is wound and having a bobbin at the end of the laminate is one of the preferred embodiments of the present invention.
An antenna for RFID to be built in planar RFID tags comprising a wound coil and a plate core of a ferromagnetic material, in which the plate core penetrates the wound coil, wherein the magnetic substrate or the laminate thereof of the present invention is used as the ferromagnetic plate core is one of the preferred embodiments of the present invention.
Furthermore, the antenna for RFID, in which the plate core described above is shape-preserving in the process of bending, is one of the preferred embodiments of the present invention.
Furthermore, in another aspect of the present invention, it provides an electric motor or an electric generator, in which the magnetic laminate is used in a part of or the whole the rotor or the stator comprising a soft magnetic material.
In another aspect of the present invention, it also provides an electric motor or an electric generator having a rotor or a stator comprising a magnetic material, characterized by the fact that at least a part of the magnetic material in the rotor or the stator is constituted of a laminate comprising an amorphous metal magnetic ribbon and the laminate comprising an amorphous metal magnetic ribbon is formed by laminating layers of a heat resistant adhesive resin and layers of the amorphous metal magnetic ribbon alternately.
In the antenna of the present invention, a magnetic substrate comprising an amorphous metal ribbon, in which the amorphous metal described above is represented by the general formula:
(Co (1−c) Fe c ) 100−a−b X a Y b
wherein X represents at least one species of element selected from the group consisting of Si, B, C and Ge, Y represents at least one species of element selected from the group consisting of Zr, Nb, Ti, Hf, Ta, W, Cr, Mo, V, Ni, P, Al, Pt, Rh, Ru, Sn, Sb, Cu, Mn and rare earth elements, c, a and b respectively satisfy 0≦c≦0.2, 10<a≦35 and 0≦b≦30, and a and b are represented in terms of atomic %, can be preferably used.
In the electric motor or the electric generator of the present invention, it is preferable to use a magnetic substrate, wherein the amorphous metal described above is represented by the general formula:
(Co (1−c) Fe c ) 100−a−b X a Y b
wherein X represents at least one species of element selected from the group consisting of Si, B, C and Ge, Y represents at least one species of element selected from the group consisting of Zr, Nb, Ti, Hf, Ta, W, Cr, Mo, V, Ni, P, Al, Pt, Rh, Ru, Sn, Sb, Cu, Mn and rare earth elements, c, a and b respectively satisfy 0.3<c≦1 0, 10<a≦35 and 0<b≦30, and a and b are represented in terms of atomic %, and the heat resistant resin described above, comprises a resin that satisfies all of the five characteristics:
- (1) the weight loss rate owing to the thermal decomposition in a thermal history of two hr in a nitrogen atmosphere at 350° C. is 1% by weight or less;
- (2) the tensile strength after a thermal history of two hr in a nitrogen atmosphere at 350° C. is 30 MPa or more;
- (3) the glass transition temperature is from 120° C. to 250° C.;
- (4) the temperature at which the melt viscosity is 1,000 Pa·s or less is not lower than 250° C. and not higher than 400° C.; and
- (5) the heat of fusion owing to crystals in the resin after being cooled from 400° C. to 120° at a ratio of 0.50° C./min is 10 J/g or less.
In another aspect of the present invention, the core used in the electric motor or the electric generator of the present invention is constituted of a laminate comprising an amorphous metal magnetic ribbon, and the laminate comprises an amorphous metal magnetic ribbon described above that it is formed by alternatively, laminating layers of heat resistant resin, whose weight loss rate owing to a thermal decomposition in a thermal history of 1 hr in a nitrogen atmosphere at 300° C. is 1% by weight or less, and layers of the amorphous metal magnetic ribbon and is comprising an amorphous metal layer having a tensile strength of 500 MPa or less and an amorphous metal layer having a tensile strength of 500 MPa or more.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an example of a laminate for antenna formed by alternately laminating amorphous metal ribbons and heat resistant resin.
FIG. 2 is an example briefly showing a laminate of magnetic substrates formed by alternately laminating amorphous metal ribbons and heat resistant resin.
FIG. 3 is an example briefly showing an antenna, wherein a conductive wire is wound on the circumference of a laminate.
FIG. 4 is an example briefly showing a method for applying a pressure on magnetic substrates in the present invention.
FIG. 5 is an example briefly showing a stator for an electric motor using the laminate of magnetic substrates of the present invention.
FIG. 6 is an example briefly showing a synchronous reluctance motor using the laminate of magnetic substrates of the present invention.
FIG. 7 is an example briefly showing a toroidal-shaped inductor using the laminate of magnetic substrates of the present invention.
In FIG. 4, 411 is a frame for the purpose of preventing slippage, 412 is a flat mold, 413 is a magnetic laminated plate, 421 is a heat resistant elastic sheet and 431 is a heating plate of the press facility.
In FIG. 6, 611 is a rotor, 612 is a stator, 613 is a coil, 621 is a rotating shaft, 622 is a shaft bearing and 630 is a case.
BEST MODES FOR CARRYING OUT THE INVENTION
(Amorphous Metal Ribbon)
The chemical composition of the amorphous metal ribbon used in the magnetic substrate of the present invention has Fe or Co as its main component and is represented by the general formula:
(Co (1−c) Fe c ) 100−a−b X a Y b
wherein X represents at least one species of element selected from the group consisting of Si, B, C and Ge, Y represents at least one species of element selected from the group consisting of Zr, Nb, Ti, Hf, Ta, W, Cr, Mo, V, Ni, P, Al, Pt, Rh, Ru, Sn, Sb, Cu, Mn and rare earth elements, c, a and b respectively satisfy 0≦c≦1.0, 10<a≦35 and 0≦b≦30, and a and b are represented in terms of atomic %.
In one aspect of the present invention, an amorphous metal that satisfies 0≦c≦0.2 or 0≦c≦0.3 is also referred to as “Co based amorphous metal” or “amorphous metal whose main component is Co” and an amorphous metal that satisfies 0.3<c≦1.0 is also referred to as “Fe based amorphous metal” or “amorphous metal whose main component is Fe”.
In the amorphous metal ribbon used in the present invention, the ratio of Co to Fe tends to contribute to increase the saturation magnetization of the amorphous metal. If the saturation magnetization is important depending on the utility, the amount of substitution, c, preferably is in the range of 0≦c≦0.2. More preferably, it is in the range of 0≦c≦0.1.
The element X is an element that tends to be effective in reducing the crystallization speed for the purpose of amorphizing to produce the amorphous metal ribbon used in the present invention. If the amount of the element X is not more than 10% by atom, the noncrystallinity may be easy to deteriorate to partly contain crystalline metal. If the amount of the element X is more than 35% by atom, the mechanical strength of the alloy ribbon may be easy to deteriorate, although amorphous structure can be obtained, and a continuous ribbon may be difficult to be obtained. Therefore, a, the amount of the element X is preferably is in the range of 10<a≦35, and preferably is in the range of 12≦a≦30.
The element Y tends to be effective in improving the corrosion resistance of the amorphous metal ribbon used in the present invention. The most effective elements among those are, Zr, Nb, Ti, Hf, Ta, W, Cr, Mo, V, Ni, P, Al, Pt, Rh, Ru, Sn, Sb, Cu, Mn an rare earth elements. If the amount of the element Y added is 30% or more, the mechanical strength of the ribbon may be easy to deteriorate, although the effect of improving corrosion resistance still exists. Therefore, it is preferable that 0≦b≦30. More preferable range is 0≦b≦20.
Furthermore, the amorphous metal ribbon used in the present invention is, for example, obtained by melting a mixture of metals in the intended chemical composition using a high-frequency melting furnace to make a homogeneous melt, and then quenching the melt by casting it on a cooling roll using an inert gas or the like to make it flow. The thickness is usually from 5 to 100 μm, preferably from 10 to 50 μm. More preferably, a ribbon having a thickness of from 10 to 30 μm is used.
The amorphous metal ribbon used in the present invention can form a laminate to be used in a member or a part of applied magnetic products of various types by being laminated. As the amorphous metal ribbon used in the magnetic substrate of the present invention, an amorphous metal material formed in sheet-like shape by liquid quench method or so on can be used. Also, a material obtained by molding a powder amorphous metal material to form a sheet like shape by press molding or so on can be used. Furthermore, as the amorphous metal ribbon used in the magnetic substrate, a single amorphous metal ribbon can be used and more than one type of amorphous metal ribbons laminated together can also be used.
Furthermore, a magnetic substrate, wherein a heat resistant resin or a precursor of the heat resistant resin is formed on at least a part of the amorphous metal ribbon described above or a magnetic substrate wherein the precursor has been resinified can be obtained.
The magnetic substrate has a good processability in press working, cutting and so on in comparison with a ribbon on which no heat resistant resin is formed.
As the Fe based amorphous metal material of the present invention, Fe-semi metal system amorphous metal materials such as Fe-Si-B system, Fe-B system and Fe-P-C system and Fe-transition metal amorphous metal materials such as Fe-Zr system, Fe-Hf system and Fe-Ti system can be preferably cited. As the Co based amorphous metal material, amorphous metal materials such as Co-Si-B system and Co-B system can be preferably cited.
As the Fe based amorphous metal material preferably used in a member or a part of an applied magnetic product that handles high power electricity, such as an electric motor or a transformer, Fe-semi metal system amorphous metal materials such as Fe-B-Si system, Fe-B system and Fe-P-C system and Fe-transition metal system amorphous metal materials such as Fe-Zr system, Fe-Hf system and Fe-Ti system can be cited. As the Fe-Si-B system, for example, Fe 78 Si 9 B 13 (at %), Fe 78 Si 10 B 12 (at %), Fe 81 Si 3.5 B 13.5 C 2 (at %), Fe 77 Si 5 B 16 Cr 2 (at %), Fe 66 Co 18 Si 1 B 15 (at %) and Fe 74 Ni 4 Si 2 B 17 Mo 3 (at %) can be cited. Among these, Fe 78 Si 9 B 13 (at %) and Fe 77 Si 5 B 16 Cr 2 (at %) are preferably used. Using Fe 78 Si 9 B 13 (at %) is especially preferable. However, the amorphous material in the present invention is not limited to these.
(Heat Resistant Resins)
Although the heat treatment temperature for the magnetic substrate varies depending on the chemical composition of the amorphous metal ribbon and magnetic properties to be obtained, the temperature that elicits good magnetic properties tends to be within the range of approximately from 300 to 500° C. Since the heat resistant resin has been formed on the amorphous metal ribbon, it is subjected to a heat treatment at a temperature appropriate to elicit magnetic properties of the magnetic substrate.
In another aspect of a heat resistant resin used in the present invention, it preferably comprises a resin that satisfies all of the following requirements:
- (1) the weight loss rate owing to a thermal decomposition in a thermal history of 2 hr in a nitrogen atmosphere at 350° C. is 1 % by weight or less;
- (2) the tensile strength after a thermal history of 2 hr in a nitrogen atmosphere at 350° C. is 30 MPa or more;
- (3) the glass transition temperature is from 120° C. to 250° C.;
- (4) the temperature at which the melt viscosity is 1,000 Pa·s or less is not lower than 250° C. and not higher than 400° C.; and
- (5) the heat of fusion owing to crystals in the resin after being cooled from 400° C. to 120° C. at a ratio of 0.5° C./min is 10 J/g or less.
For example, the weight loss rate of the heat resistant resin in the present invention when kept in a nitrogen atmosphere at 350° C. for 2 hr after a drying at 120° C. for 4 hr as a pre-treatment, measured using a differential thermal analyzer and thermogravimeter, DTA-TG, is preferably 1% or less, more preferably 0.3% or less. The effect of the invention can be fully displayed in these ranges. Using a resin having a greater weight loss is not preferable as a breaking off or swelling of the laminate may happen.
The tensile strength test is for example, carried out according to ASTM D-638 on a predetermined type of specimen made of a resin that have been heat treated in a nitrogen atmosphere at 350° C. for 2 hr. The tensile strength is usually 30 MPa or more, preferably 50 MPa or more. If the tensile strength is out of the range, effects, such as good shape stability, may not be easy to be displayed.
The glass transition temperature, Tg, of the heat resistant resin in the present invention is for example, determined from a point of inflection on the endothermic curve that shows glass transition measured using a differential scanning calorimeter, DSC. The Tg is not less than 120° C. and not more than 250° C., preferably not more than 220° C. When the Tg is too high, it may be difficult to prevent from deterioration of the magnetic properties.
In one aspect, it is important that the heat resistant resin of the invention shows thermoplasticity. When it is applied for the present invention in a form of varnish, a resin that can be melted by heating is used, even when it is apparently used like a thermosetting resin.
The temperature, at which the melt viscosity measured for example, using a Koka-type flow tester is 1,000 Pa·s or less, is usually 250° C. or more and usually 400° C. or less, preferably 350° C. or less, more preferably 300° C. or less. When the temperature, at which the melt viscosity is 1,000 Pa·s or less, is in the range like this, heat press adhesion of the present invention can be carried out at low temperatures and the effect of excellent adhesion properties can be displayed. When the temperature at which the melt temperature goes down is too high, adhesion failure may occur.
Preferably, the heat of fusion owing to crystalline constituents existing in the resin after cooling the heat resistant resin from 400° C. to 120° C. at a constant rate of 0.5° C./min is 10 J/g or less, more preferably 5 J/g or less, much more preferably 1 J/g or less. When it is in the range like this, an excellent adhesion property, which is one of the effects of the present invention, can be fully displayed.
Although no particular limitation is imposed on the molecular weight and the molecular weight distribution of the heat resistant resin to be used, it is preferable that the value of logarithmic viscosity measured after dissolving the resin in a solvent that is capable of dissolving the resin at a concentration of 0.5 g/100 ml at 35° C. be 0.2 dl/g or more, since there is a concern that the strength of the resin coating of the coated substrate and the adhesive strength are adversely influenced in case that the molecular weight is extremely low.
(Type of the Heat Resistant Resin)
As examples of the resin which is suitable for the condition described above but not limited, polyimide resins, ketone resins, polyamide resins, nitrile resins, thioether resins, polyester resins, arylate resins, sulfone resins, imide resins and amide-imide resins can be cited. In the present invention, it is preferable to use a polyimide resin, a ketone resin or a sulfone resin.
The heat resistant resin used in the present invention is preferably an aromatic polyimide resin that has one or more types of repeating units selected from the group consisting of those represented by the chemical formulae (1) to (4) in the main chain skeleton and having a ratio of aromatic rings having bonds in meta position to total aromatic rings in the repeating unit is from 20 to 70 mol %.
In the formulae (1) to (4), each of X represents a bivalent bonding group selected from a group consisting of direct bond, ether bond, isopropylidene bond and carbonyl bond and can be the same or different; and each of R is a tetravalent bonding group selected from a group consisting of the groups represented by chemical formulae (5) to (10) and can be the same or different.
One of the methods of preparing for polyimides but not limited, is described below. These polyimides can be prepared from an aromatic diamine and an aromatic tetracarboxylic acid by polycondensation.
As the aromatic diamine, a dinuclear compound having two aromatic rings is used to obtain a polyimide represented by the chemical formula (1); a trinuclear compound having three aromatic rings is used to obtain a polyimide represented by the chemical formula (2); a tetranuclear compound having four aromatic rings is used to obtain a polyimide represented by the chemical formula (3); and a mononuclear compound having one aromatic ring is used to obtain a polyimide represented by the chemical formula (4).
- (i) As the mononuclear compound, p-phenylenediamine, m-phenylenediamine and so on;
- (ii) as the dinuclear compound, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl sulfide, 3,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfone, 3,4′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfone, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 2-(3-aminophenyl)-2-(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2-(3-aminophenyl)-2-(4-aminophenyl)-1,1,1,3,3,3-hexafluoro-p ropane and so on;
- (iii) as the trinuclear compound, 1,1-bis(3-aminophenyl)-1-phenylethane, 1,1-bis(4-aminophenyl)-1-phenylethane, 1-(3-aminophenyl)-1-(4-aminophenyl)-1-phenylethane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminobenzoyl)benzene, 1,3-bis(4-aminobenzoyl)benzene, 1,4-bis(3-aminobenzoyl)benzene, 1,4-bis(4-aminobenzoyl)benzene, 1,3-bis(3-amino-α,α-dimethylbenzyl)benzene, 1,3-bis(4-amino-α,α-dimethylbenzyl)benzene, 1,4-bis(3-amino-α,α-dimethylbenzyl)benzene, 1,4-bis(4-amino-α,α-dimethylbenzyl)benzene, 1,3-bis(3-amino-α,α-ditrifluoromethylbenzyl)benzene, 1,3-bis(4-amino-α,α-ditrifluoromethylbenzyl)benzene, 1,4-bis(3-amino-α,α-ditrifluoromethylbenzyl)benzene, 1,4-bis(4-amino-α,α-ditrifluoromethylbenzyl)benzene, 2,6-bis(3-aminophenoxy)benzonitrile, 2,6-bis(3-aminophenoxy)pyridine and so on; and
- (iv) as the tetranuclear compound, 4,4′-bis(3-aminophenoxy)biphenyl, 4,4′-bis(4-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]ketone, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoroprop ane, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoroprop ane and so on; can be cited, respectively. However it is not limited to the diamines cited. The bond between the aromatic rings of the dinuclear or trinuclear compound of the aromatic diamine is preferably a ether bond.
Among the aromatic diamines described above, 4,4′-bis(3-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy)phenyl]ketone, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]ether, 2,2-bis[4-(3-aminophenoxy)phenyl]propane and 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoroprop ane are used as particularly preferable species.
Concrete examples of the tetracarboxylic dianhydride for preparing the polyimide resin used in the present invention include, for example, pyromellitic dianhydride, 3,3′,4,4′-benzophenone tetracarboxylic dianhydride, 2,3′,3,4′-benzophenone tetracarboxylic dianhydride, 3,3′,4,4′-biphenyl tetracarboxylic dianhydride, 2,3′,3,4′-biphenyl tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 2,2-bis{4-(3,4-dicarboxyphenoxy)phenyl}propane dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride and so on. However, it is not limited to the tetracarboxylic dianhydrides cited.
Among these, pyromellitic dianhydride and one or more species of tetracarboxylic dianhydride selected from the followings can be preferably used in combination. As the preferable tetracarboxylic dianhydride can be combined, 3,3′,4,4′-benzophenone tetracarboxylic dianhydride, 3,3′,4,4′-biphenyl tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride and 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride can be preferably used. The combination of the diamine and the tetracarboxylic dianhydride above can be the same combination or different combinations.
Among combinations of the diamine and the tetracarboxylic dianhydride, such a combination that a ratio of aromatic rings having bonds in meta position to total aromatic rings in a repeating unit is from 20 to 70 mol % is preferably employed. The ratio of aromatic rings having bonds in meta position to total aromatic rings in a repeating unit can be calculated in the following manner. In the chemical formula (25), for example, the repeating unit has totally 4 aromatic rings and two of them in the diamine part are bonded in meta position, so the ratio of aromatic rings having bonds in meta position is calculated to be 50%. Bonding positions of aromatic rings can be confirmed using nuclear magnetic resonance spectra or infrared absorption spectra.
The heat resistant resin of the present invention is preferably an aromatic polyimide resin characterized by comprising a repeating unit represented by the chemical formula (11) or (12) in the main chain skeleton.
In the formula (11) and (12) above, a tetravalent bonding group selected from the formulae (5) to (10), which can be the same or different, is preferably used as R.
A resin comprising an aromatic polyimide resin having a repeating unit represented by the chemical formula (13) in the main chain skeleton is preferable as the heat resistant resin used in the present invention.
In the formula (13) above, X is a divalent bonding group selected from direct bond, ether bond, isopropylidene bond or carbonyl bond and can be the same or different. Also in the formula (13), a and bare numbers that satisfy the relationships, a+b=1, 0<a<1 and 0<b<1.
No limitation is imposed on the process for producing the heat resistant resin used in the present invention and any publicly known method can be used. No limitation is imposed on the repeating structure of the constituent units of the heat resistant resin used in the resin composition of the present invention and any of the alternating structure, random structure and block structure is applicable. Graft structure is also applicable.
The polymerization reaction is preferably carried out in an organic solvent. As the organic solvent used for the reaction like this, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, N,N-diethylacetamide, N,N-dimethoxyacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam, 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethoxy)ethyl]ether, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, pyrroline, picoline, dimethylsulfoxide, dimethylsulfone, tetramethylurea, hexamethylphosphoramide, phenol, o-cresol, m-cresol, p-chlorophenol, anisole, benzene, toluene, xylene and so on can be cited. These organic solvents can be employed solely or as a mixture of two or more species.
In the step of application the polyimide in the present invention on an amorphous metal ribbon, although the polyimide itself can be appropriately applied, it can be for example, applied as a resin solution. Also a precursor of the polyimide can be applied in the step of application. When using a soluble polyimide resin, the resin can be dissolved in a solvent to form a liquid. The viscosity can be adjusted to an appropriate value. The solution can be applied on an amorphous metal ribbon and then be heated to vaporize the solvent to form the resin.
In the polyamide used in the present invention, the molecular weight can be adjusted for example, by shifting the molar ratio between the diamine and the aromatic tetracarboxylic dianhydride used from the theoretically equivalent value, as far as it does not adversely affect the properties of the polyimide itself, when preparing a polyamic acid prior to the imidization. Although no particular limitation is imposed on the molecular weight and the molecular weight distribution of the heat resistant resin used in the present invention, for example, the value of the logarithmic viscosity measured after dissolving the resin in a solvent that can dissolve the resin at a concentration of 0.5 g/100 ml at 35° C. is preferably not less than 0.2 dl/g and not more than 2.0 dl/g.
In the polyamide used in the present invention, the molecular weight can be adjusted by shifting the molar ratio between the diamine and the aromatic tetracarboxylic dianhydride used from the theoretically equivalent value, as far as it does not seriously affect the properties of the polyimide itself, when preparing a polyamic acid prior to the imidization. In this case, the surplus amino group or acid anhydride group can be deactivated by being reacted with an aromatic dicarboxylic anhydride or an aromatic monoamine whose amount is not less than the theoretical equivalent of the surplus amino group or acid anhydride group.
Although no particular limitation is imposed on the amount and the type of the impurity contained in the resin, it is preferable that the total amount be 1 wt % or less and the total amount of the ionic impurities such as sodium or chlorine be 0.5 wt % or less, since the impurity may adversely affect the effect of the invention in some applications.
Furthermore, it is preferable to use an aromatic polysulfone resin (formula) having one type or two or more types of repeating unit(s) selected from the repeating units represented by the chemical formulae (14) to (15) in the main chain skeleton in the heat resistant resin of the present invention.
The value of the logarithmic viscosity measured after dissolving the resin in a solvent that can dissolve the resin at a concentration of 0.5 g/100 ml at 35° C. is preferably not less than 0.2 dl/g and not more than 2.0 dl/g. For example, a polyethersulfone manufactured by Mitsui Chemicals, Inc. such as E1010, E2010 and E3010 and those manufactured by Amoco Engineering such as UDEL P-1700 and P-3500 can be used.
(Application of Heat Resistant Resin)
In the present invention, the heat resistant resin is applied on at least a part of a side or at least a part of both sides of the amorphous metal ribbon. In this step, it is preferable that the resin be coated homogeneously and without unevenness on the side to be applied. For example, in case of making a magnetic substrate laminate, in which magnetic substrates are laminated, the structure of the laminate can be designed freely by stacking using a method, such as multi-layer lamination, heat press, heat roll or high frequency welding. When applying the heat resistant resin on at least a part of a side or the both sides of the amorphous metal ribbon, the resin can be in the form of a powder resin, a solution in which the resin is dissolved in a solvent or a paste. When a solution in which the resin is dissolved is used, it is a typical way to apply it on the amorphous metal ribbon using a roll coater or the like. In the case of the application using a solution in which the resin is dissolved in a solvent, the viscosity of the resin solution used in the application step is ordinarily but not limited, in the concentration range of from 0.005 to 200 Pa·s, preferably from 0.01 to 50 Pa·s, more preferably from 0.05 to 5 Pa·s. If the viscosity is 0.005 Pa·s or less, the viscosity is so low that the solution flows out of the amorphous metal ribbon, the amount of the coating on the ribbon may be not enough, and then the coating may become extremely thin. Furthermore, if the application is carried out at an extremely low speed in order to make the coating thick enough in this case, it is necessary to carry out several times of recoating, which makes the production efficiency low, namely not so practical. On the other hand, if the viscosity is 200 Pa·s or more, it is not easy to control the film thickness in order to form a thin coated film on an amorphous metal film because of the high viscosity.
As examples of the method for applying liquid resin in the present invention, methods using a coater such as roll coater method, gravure coater method, air doctor coater method, blade coater method, knife coater method, bar coating method, rod coater method, kiss coater method, bead coater method, cast coater method and rotary screen method; dip coating method, in which coating is carried out while an amorphous metal ribbon is dipped in liquid resin; and slot orifice coater method, in which liquid resin is dropped from an orifice on an amorphous metal ribbon; and so on can be used. Furthermore, any method that is capable of applying a heat resistant resin on an amorphous metal ribbon such as spray coating method in which liquid resin is sprayed on an amorphous metal ribbon using the principle of the spray, spin coating method, electrodeposition coating method, physical deposition method such as sputtering method and gas phase method such as CVD method can be used.
Furthermore, application of the heat resistant resin on a part can be carried out for example, by gravure coater method using a gravure head whose slot of the coating pattern has been processed.
A resin in a form of paste is preferably used as the resin to be applied on at least a part of a side or on at least a part of both sides of the amorphous metal ribbon of the present invention, mainly in such cases that amorphous metal ribbons that have been cut are laminated. For this purpose, the resin preferably has such a viscosity that makes temporal fixing or temporal adhesion possible rather than the flowability possessed by a solution in which a resin is dissolved in a solvent. The paste can be applied according to methods such as potting and brushing. In this case, the viscosity of the resin is preferably 5 Pa·s or more. On the other hand, as an example of the case in which resin powder is used, such a process that a laminate of amorphous metal ribbons is prepared using a mold, wherein resin powder or pellet is filled in or dispersed and then a laminate of amorphous metal ribbons are prepared by means of heat press, can be cited.
In the present invention, a magnetic substrate means an article wherein a resin is applied on an amorphous metal ribbon. The amorphous metal ribbon can be one that has been subjected to a heat treatment for the purpose of improving properties as a magnetic material or one that has not been subjected to the heat treatment. The magnetic substrate of the present invention can be subjected to a heat treatment for the purpose of eliciting properties as a magnetic material even after the application of the heat resistant resin. When a precursor of the heat resistant resin is applied on the amorphous metal ribbon, a heat treatment must be carried out to form the heat resistant resin. Although this heat treatment is usually carried out at a temperature lower than that of the heat treatment to improve magnetic properties, both treatments can be carried out simultaneously. That is, in one aspect of the magnetic substrate of the present invention, it can be produced according to any method of the following methods.
- (a) a method, in which a heat resistant resin is applied on an amorphous metal ribbon that has not been subjected to a heat treatment for the purpose of improving magnetic properties;
- (b) a method, in which a precursor of a heat resistant resin is applied on an amorphous metal ribbon that has not been subjected to a heat treatment for the purpose of improving magnetic properties and then a heat resistant resin is formed chemically or thermally (step A);
- (c) a method, in which a heat resistant resin is applied on an amorphous metal ribbon that has been subjected to a heat treatment for the purpose of improving magnetic properties;
- (d) a method, in which a precursor of a heat resistant resin is applied on an amorphous metal ribbon that has been subjected to a heat treatment for the purpose of improving magnetic properties and then a heat resistant resin is formed chemically or thermally (step A); and
- (e) a method, in which a laminate is produced according to one of the methods of (a) to (d) and then the laminate is further subjected to a heat treatment for the purpose of improving magnetic properties, can be cited. Preferably, methods defined in (a) and (b) are employed, and it is preferable to carry out the heat treatment of (e) after the treatment defined in (a) or (b) is carried out.
In the methods of (a) and (b), the amorphous metal ribbon is not subjected to a heat treatment, so the ribbon has not become brittle. Therefore it is possible to wind the ribbon. Furthermore, since the heat resistant resin is applied on the amorphous metal ribbon, the progress of a crack is suppressed even if the ribbon has a pinhole, the winding speed can be high, and thus the industrial mass-productivity is excellent.
In the case of preparing a laminate having a multi-layered structure wherein a heat resistant resin is applied on amorphous metal ribbons, multi-layer coating method is applied or single-layer coated or multi-layer coated substrates are laminated by pressurizing using, for example, a heat press or a heat roll. Although the temperature in the pressurizing step varies depending on the type of the heat resistant resin, it is generally preferable to laminate at a temperature not less than the glass transition temperature (Tg) of the cured resin and close to the temperature at which the resin softens or melts.
(Laminate)
In one aspect of the magnetic substrate of the present invention, it is an article wherein a heat resistant resin is applied on an amorphous metal ribbon. Although it can be used as a single layer article, it can also be used as in a laminate of magnetic substrates by laminating it.
In preparing the laminate of a magnetic substrate, the laminate of a structure that has been freely designed can be prepared by stacking and adhering utilizing multi-layer coating method, heat press method, heat roll method, high frequency welding method and so on.
For the preparation of the laminated magnetic substrate, utilization of the following steps can be considered depending on whether a heat treatment for the purpose of improving magnetic properties has been carried out, type of the heat resistant resin, whether a precursor of the heat resistant resin is used, when the heat resistant resin is formed from the precursor thereof and when the heat treatment for the purpose of improving magnetic properties is carried out. The magnetic substrate of the present invention is prepared by one of the following steps or a combination of two or more of them.
(1) Step A: A precursor of a heat resistant resin is applied on an amorphous metal ribbon and the intended resin is formed by a heat treatment or a chemical method such as a method in which a chemical-reactive substituent is used.
(2) Step B: This is a step of lamination in which the lamination is carried out by pressure bonding using a press or so on. It can be used as obtained, or the ribbons can be fusion-bonded each other by melting the resin applied on the amorphous ribbons to further proceed to the next step. Furthermore, a heat treatment can be carried out in order to improve magnetic properties of the amorphous metal ribbons. In any case, a heat resistant resin exists between the amorphous metal ribbons, and the “laminate” means a status like this.
(3) Step C: Amorphous metal ribbons can be unified with each other more firmly by melting the resin applied on the metal ribbons. The heat treatment is usually carried out at from 50 to 400° C., preferably from 150 to 300° C. Step B and Step C are usually carried out simultaneously by heat-press method or the like.
(4) Step D: This step is a heat treatment for the purpose of improving magnetism, more specifically is a heat treatment which is carried out for the purpose of improving magnetic properties of the amorphous metal ribbons. Although the heat treatment temperature of the amorphous metal ribbon varies depending on the composition constituting the amorphous metal ribbon and the intended magnetic properties, the treatment is usually carried out in an inert gas atmosphere or in vacuum, and the temperature that improves the magnetic properties is from about 300 to 500° C., preferably from 350 to 450° C.
By combining the steps till Step D including Step A, in which the heat resistant resin or the precursor is applied, described above, a laminate wherein the magnetic substrate of the present invention is used and laminated can be produced.
As the concrete examples of the combination, the combined methods represented by the followings can be cited. More than one of the steps described above can be carried out simultaneously. The examples are:
- (i) a method, in which magnetic substrates that have not been subjected to a heat treatment for the purpose of improving magnetic properties are stacked, and then a laminate is formed by fusion bonding (In the method, Step B and Step C are carried out simultaneously.);
- (ii) a method, in which magnetic substrates that have been subjected to a heat treatment for the purpose of improving magnetic properties are stacked and then are fusion bonded to form a laminate (In the method, Step B and Step C are carried out simultaneously.);
- (iii) a method, in which a precursor of a heat resistant resin is used, and magnetic substrates that have not been subjected to a heat treatment for the purpose of improving magnetic properties are laminated and then formation of the heat resistant resin and formation of the laminate are carried out simultaneously (In the method, Step B and Step C are carried out simultaneously.);
- (iv) a method, in which a precursor of a heat resistant resin is used, and magnetic substrates that have been subjected to a heat treatment for the purpose of improving magnetic properties are stacked and then formation of the heat resistant resin and formation of the laminate are carried out simultaneously (In the method, Step B and Step C are carried out simultaneously.);
- (v) a method, in which a heat treatment for the purpose of improving magnetic properties is further carried out after the laminated magnetic substrates are produced according to any of the methods described in (i) to (iv) above (Step D); and
- (vi) a method, in which magnetic substrates on which a heat resistant resin or a precursor of a heat resistant resin is applied are stacked and then a heat treatment to improve magnetic properties and laminate-adhesion are carried out simultaneously (In the method, Step C and Step D are carried out simultaneously.), can be cited. Among these, a method, in which (iii) is carried out after (i) being carried out, or a method, in which (vi) is carried out after both of (i) and (iii) are carried out, is preferably employed.
In making a laminate, the needed number of single-layer substrates can be laminated to form the laminate, or laminates can be laminated to form the laminate. In the case that a precursor of a heat resistant resin is used, formation of the laminate can be carried out simultaneously with the formation of the heat resistant resin.
A laminate having an appropriate number, which varies depending on the intended application, of layers is used. Each layer of the laminate can be the same type of magnetic substrate, and can be the different type of magnetic substrate.
(Method for Pressurized Heat Treatment)
It is a characteristic of the present invention that a resin is applied in some way on a side or on both sides of an amorphous metal ribbon that is represented by a general formula:
(Co (1−c) Fe c ) 100−a−b X a Y b
wherein X represents at least one species of element selected from the group consisting of Si, B, C and Ge, Y represents at least one species of element selected from the group consisting of Zr, Nb, Ti, Hf, Ta, W, Cr, Mo, V, Ni, P, Al, Pt, Rh, Ru, Sn, Sb, Cu, Mn and rare earth elements, c, a and b respectively satisfy 0≦c≦1.0, 10<a≦35 and 0≦b≦30, and a and b are represented in terms of atomic %, and then the ribbon is pressurized and heated treated to improve the magnetic properties.
The pressurized heat treatment is usually carried out under an applied pressure of from 0.01 to 500 MPa and at a temperature of from 200 to 500° C. The treatment can be carried out at a single time or can be carried out in two or more steps. When it is carried out in two or more steps, the conditions of the steps can be different.
(Process for Producing a Magnetic Substrate Whose Main Component is Co)
As a process for producing a magnetic substrate whose main component is Co, a process, in which magnetic substrates obtained by applying a resin on a side or on both sides of an amorphous metal ribbon having an element composition represented by the formula (Co (1−c) Fe c ) 100−a−b X a Y b (In the formula X represents at least one species of element selected from the group consisting of Si, B, C and Ge, Y represents at least one species of element selected from the group consisting of Zr, Nb, Ti, Hf, Ta, W, Cr, Mo, V, Ni, P, Al, Pt, Rh, Ru, Sn, Sb, Cu, Mn and rare earth elements, c, a and b respectively satisfy 0≦c≦0.3, 10<a≦35 and 0≦b≦30.) are stacked, and then adhesion of the amorphous metal ribbon with the resin and a heat treatment for the purpose of improving magnetic properties are usually carried out simultaneously under the condition of an applied pressure of from 0.01 to 100 MPa, a temperature of from 350 to 480° C. and time period of from 1 to 300 min, is preferably employed.
The laminate-adhesion of the magnetic laminate and the heat treatment for the purpose of improving the magnetic properties are explained below. When the laminate is used in a form of a closed magnetic path or a semiclosed magnetic path, such as a small gap, the condition of an applied pressure is preferably from 0.01 to 100 MPa, more preferably from 0.03 to 20 MPa, further preferably from 0.1 to 3 MPa. A pressure of 0.01 MPa or less is not preferable, as insufficient adhesion, which may cause for example, easy-deterioration of the tensile strength of the laminate may take place. A pressure exceeding 100 MPa is not also preferable, as insufficient magnetic properties including decrease in the relative magnetic permeability and increase in the core loss may take place. The temperature condition for carrying out the laminate-adhesion and the heat treatment for the purpose of improving the magnetic properties simultaneously is preferably from 350 to 480° C., more preferably from 380 to 450° C., further preferably from 400 to 440° C. If it is less than 350° C. or more than 480° C., problems, such as insufficient magnetic properties, may take place owing to the fact that an appropriate heat treatment to improve magnetic properties can not be carried out. The time condition for carrying out the laminate-adhesion and the heat treatment for the purpose of improving the magnetic properties simultaneously is preferably from 1 to 300 min, more preferably from 5 to 200 min, further preferably from 10 to 120 min. If the time is less than 1 min or more than 300 min, it is not preferable as insufficient magnetic properties owing to the fact that an appropriate heat treatment to improve magnetic properties can not be carried out or deterioration of the tensile strength of the laminate owing to insufficient adhesion may take place.
If it is used in the form of open magnetic path on the other hand, the pressure condition to be applied is not less than 1 MPa and not more than 500 MPa, preferably not less than 3 MPa and not more than 100 MPa, more preferably not less than 5 MPa and not more than 50 MPa. If an applied pressure is too low, Q value decreases or the effect of increasing Q value is not enough, and if it is greater than 500 MPa, Q value may deteriorate. Particularly, if the effective magnetic permeability as a result of a shape effect is not more than ½, preferably not more than 1/10, more preferably not more than 1/100, that of the magnetic permeability of the material in case of closed magnetic path, Q value is improved in such a condition that an applied pressure is too high.
Furthermore, the temperature condition that improves the magnetic properties of the amorphous metal ribbon is usually from 300° C. to 500° C. Although the condition varies depending on the composition that constitutes the amorphous metal ribbon and the intended magnetic properties, it is usually carried out in an inert gas atmosphere or in vacuo. And the temperature that improves the magnetic properties to excellent values is usually from about 300° C. to 500° C., preferably is from 350° C. to 450° C.
The treatment time at the heat treatment temperature is usually from 10 min to 5 hr, preferably from 30 min to 2 hr.
No particular limitation is imposed on the process in which laminate-adhesion of the magnetic substrates and the heat treatment for the purpose of improving the magnetic properties are carried out simultaneously. For example, a method in a heat press, a method in which lamination and fixation is carried out using a device and then a heat treatment is carried out and so on are cited as preferable methods. Furthermore, when the laminate-adhesion of the magnetic substrates and the heat treatment for the purpose of improving the magnetic properties are carried out simultaneously, the process is preferably carried out in an inert gas, such as nitrogen, atmosphere.
(Process in Which Heat Treatments are Carried Out Twice)
A method in which the magnetic substrates described above, on which a resin is applied on a side or on both sides, are stacked, and laminate-adhesion is usually carried out under the condition of an applied pressure of from 0.01 to 500 MPa at a temperature of from 200 to 350° C. for a time period of from 1 to 300 min, and then a heat treatment for the purpose of improving the magnetic properties are usually carried out under the condition of an applied pressure of from 0 to 100 MPa at a temperature of from 300 to 500° C. for a time period of from 1 to 300 min is preferably used.
The applied pressure condition of laminate-adhering the magnetic substrates is preferably from 0.01 to 500 MPa, more preferably from 0.03 to 200 MPa, further preferably from 0.01 to 100 MPa. If the pressure is less than 0.01 MPa, it is not preferable as the deterioration of the tensile strength of the laminate owing to an insufficient adhesion may take place. If the pressure is more than 500 MPa, it is not also preferable as insufficient magnetic properties including decrease in the relative magnetic permeability and increase in the core loss may take place. The temperature condition of laminate-adhering the magnetic substrates is preferably from 200 to 350° C., more preferably from 250 to 300° C. If it is less than 200° C., problems, such as the deterioration of the tensile strength of the laminate owing to an insufficient adhesion, may take place. If the temperature is more than 350° C. and the applied pressure is too high, it is not preferable as insufficient magnetic properties including decrease in the relative magnetic permeability and increase in the core loss may take place. The time condition of laminate-adhering the magnetic substrates is preferably from 1 to 300 min, more preferably from 5 to 200 min, further preferably from 10 to 120 min. If it is less than 1 min or more than 300 min, problems, such as the deterioration of the tensile strength of the laminate owing to an insufficient adhesion, may take place.
In the second heat treatment for the purpose of improving the magnetic properties of the magnetic substrate or the laminate of magnetic substrates, if the laminate is to be used in a form of a closed magnetic path or a semiclosed magnetic path, such as a small gap, the condition of an applied pressure is preferably from 0 to 100 MPa, more preferably from 0.01 to 20 MPa, further preferably from 0.1 to 3 MPa. Exceeding 100 MPa, it is not preferable as insufficient magnetic properties including decrease in the relative magnetic permeability and increase in the core loss may take place. The temperature condition for carrying out the heat treatment on the laminate-adhered laminate for the purpose of improving magnetic properties is preferably from 350 to 480° C., more preferably from 380 to 450° C., further preferably from 400 to 440° C. If the temperature is less than 350° C. or more than 480° C., it is not preferable as insufficient magnetic properties may take place owing to the fact that an appropriate heat treatment to improve magnetic properties can not be carried out or so on. The time condition for carrying out the heat treatment on the laminate-adhered laminate for the purpose of improving the magnetic properties is preferably from 1 to 300 min, more preferably from 5 to 200 min, further preferably from 10 to 120 min. Being less than 1 min or more than 300 min, it is not preferable as insufficient magnetic properties owing to the fact that an appropriate heat treatment to improve magnetic properties can not be carried out or so on may take place.
In the second heat treatment, if the laminate is to be used in the form of an open magnetic path on the other hand, the pressure condition to be applied is usually not less than 1 MPa and not more than 500 MPa, preferably not less than 3 MPa and not more than 100 MPa, more preferably not less than 5 MPa and not more than 50 MPa. If the applied pressure is too low, it is not preferable, as it may occur that Q value decreases or the effect of increasing Q value is not enough. If the applied pressure is greater than 500 MPa, it is also not preferable, as it may occur that Q value deteriorates. Particularly, If the effective magnetic permeability as a result of the shape effect is usually not more than ½, preferably not more than 1/10, more preferably not more than 1/100, of the magnetic permeability of the material in case of a closed magnetic path, Q value is improved in such a condition that an applied pressure is too high.
Furthermore, the temperature condition that improves the magnetic properties of the amorphous metal ribbon is usually from 300° C. to 500° C. Although the condition varies depending on the composition that constitutes the amorphous metal ribbon and the intended magnetic properties, it is usually carried out in an inert gas atmosphere or in vacuo. And the temperature to improve the magnetic properties to excellent values is usually from about 300° C. to 500° C., preferably is from 350° C. to 450° C.
The treatment time at the heat treatment temperature is usually from 10 min to 5 hr, preferably from 30 min to 2 hr.
The process is not limited to those for producing a magnetic substrate, in which a resin is applied on a side or on both sides of an amorphous metal ribbon. For example, a process, wherein a solution in which a resin or a precursor of the resin is dissolved is thinly applied on an amorphous metal ribbon, and then the solvent is dried off, can be preferably used.
In the magnetic substrate of amorphous metal ribbons whose main component is Co of the present invention, a thermoplastic heat resistant resin is preferably used as the resin to be used as a medium for laminate-adhesion. Although no limitation is imposed on the resin as far as the effect of the invention is displayed, a thermoplastic resin having the properties of the tensile strength measured at 30° C. after a thermal history of two hr in a nitrogen atmosphere at 365° C. of 30 MPa or more and the weight loss rate owing to a thermal decomposition in a thermal history of 2 hr in a nitrogen atmosphere at 365° C. of 2% by weight or less can be preferably used. Particularly, polyimide resins, polyetherimide resins, poly amide-imide resins, polyamide resins, polysulfone resins and polyetherketone resins are preferably used. More particularly, a resin having a repeat unit represented by one of the chemical formulae (14) to (23) can be preferably used. In the formulae (16) and (21), variables represented by a, b, c and d, each satisfies 0≦a≦1, 0≦b≦1, a+b=1, 0≦c
≦1, 0≦d≦1, a+b=1. And X, Y and Z represented in the formulae (16) and (17) are individually same as the definition of X represented in the formulae (1) to (4).
(Process for Producing a Magnetic Substrate Whose Main Component is Fe)
Although the conditions vary depending on the composition constitutes the amorphous metal ribbon and the intended magnetic properties, the process is usually carried out in an inert gas atmosphere or in vacuum, and the temperature at which magnetic properties are excellently improved is usually about from 300 to 500° C., preferably from 350 to 450° C. More preferably, from 360° C. to 380° C. is preferable. In one aspect of the present invention, the laminate can be subjected to a pressurized heat treatment, in a temperature range of from 300° C. to 500° C., and the applied pressure in this step is not more than 0.2 MPa and not less than 5 MPa. More preferably, it is subjected to a pressurized heat treatment at not more than 0.3 MPa and not less than 3 MPa. In another aspect of the present invention, by carrying out a pressurized heat treatment under an applied pressure of from 0.2 MPa to 5 MPa in a temperature range of from 300° C. to 500° C., surprisingly, the magnetic properties (magnetic permeability, iron loss) of the laminate are significantly improved, and a laminate whose mechanical properties (tensile strength) are significantly improved in comparison with those laminated and unified at 300° C. or less can be obtained.
Particularly, in applications in rotating machines such as electric motors and electric generators, improvement in performances such as increase in rotation frequency is possible owing to the improvement in mechanical strength. Therefore, significant improvement in the properties of electric motor (output power) in practice is expected.
Although the inventors do not intend to stick to a particular theory, the following can be considered to be one of the reasons of the improvement in the magnetic properties described above. At first, an amorphous metal is usually prepared by rapidly cooling a molten metal, and the residual stress in the metal originated in the cooling process impairs the magnetic properties. So, a heat treatment at from 300° C. to 500° C. is usually carried out, which is a measure to relax the internal stress, to improve the magnetic properties. In cases wherein lamination and unification are carried out by applying an external pressure and a heat treatment is usually carried out in a temperature range of from 300° C. to 500° C. as in the present invention, if the external applied pressure is too high, the internal stress in the metal owing to the pressure remains to impair the magnetic properties when the temperature of the laminate is reset to room temperature after the heat treatment. In one aspect of the present invention therefore, an applied pressure in the heat treatment process that does not impair properties of the amorphous metal has been intensively investigated, and as a result, we consider that the magnetic properties can be significantly improved with out reducing the lamination factor by carrying out a heat treatment under the applied pressure condition of not less than 0.2 MPa and not more than 5 MPa, preferably not less than 0.3 MPa and not more than 3 MPa, more preferably not less than 0.3 MPa and not more than 1.5 MPa.
Furthermore, fluctuation in the magnetic properties in the laminate after the heat treatment can be significantly improved by inserting a heat resistant elastic sheet having a thickness greater than the thickness tolerance of the laminate in the step of press pressurizing between the magnetic laminate and a planar mold used in the step of laminate-unification. In the heat resistant elastic sheet, if the sheet is made of a resin, the resin preferably has a glass transition temperature that is not less than the heat treatment temperature of the amorphous metal and higher than the glass transition temperature of the resin applied on the amorphous metal ribbon used in the magnetic substrate. As examples of the material for the heat resistant elastic sheet, polyimide resins, silicon-containing resins, ketone resins, polyamide resins, liquid crystal polymers, nitrile resins, thioether resins, polyester resins, arylate resins, sulfone resins, imide resins and amide-imide resins can be cited. Among these, polyimide resins, sulfone resins and amide-imide resins are preferably used. However, the material for the heat resistant elastic resin is not limited to those described above, and it is possible to use an elastic material, such as metal, ceramic and glass.
(Applied Magnetic Products)
The magnetic substrate or the laminate of magnetic substrates of the present invention can be used as a member of a part of various types of applied magnetic products.
As an example of an antenna made of the magnetic substrate of the present invention or used thereof as a core wound by coated conducting wire, can be cited; a thin antenna characterized by having an insulation on at least a part of the core where the wire is wound; a thin antenna characterized by having an insulation on at least a part of the core where the wire is wound and further having a bobbin at the end of the laminate; an antenna for RFID to be built in planar RFID tags comprising a wound coil and the ferromagnetic plate core made of the magnetic substrate of the present invention or the laminate thereof, which penetrates a wound coil; an antenna for RFID wherein the plate core is shape-preserving in the process of bending and so on.
An electric motor or an electric generator, wherein the magnetic substrate or the laminate of magnetic substrates of one aspect of the present invention is used in a part of or the whole the rotor or the stator comprising a soft magnetic material can be cited. As the rotor or the stator noted above, a rotor or a stator, wherein at least a part of the magnetic material(s) of the rotor or the stator is constituted of a laminate comprising an amorphous metal magnetic ribbon, and the laminate comprising the amorphous metal magnetic ribbon is formed by stacking layers of a heat resistant adhesive resin and layers of an amorphous metal magnetic ribbon alternately, can be used.
(Antenna)
An example of the laminate for antenna of the present invention, wherein amorphous metal ribbons and heat resistant resin are laminated alternately, is shown in FIG. 1. As shown in FIG. 2, amorphous metal ribbons ( 21 in FIG. 2) and heat resistant resin ( 22 in FIG. 2) are laminated alternately in the laminate. An antenna is prepared by winding a coil of conducting wire ( 31 in FIG. 3) on the circumference of the laminate as shown in FIG. 3. In evaluating the antenna performance, L value, which is the inductance as an antenna coil, and Q value (Quality Factor) is used as alternative characteristics that represent conversion characteristics between electric waves and voltages. High L values and high Q values are generally preferable. Particularly for using in a thin type bar antenna, an antenna core having a high Q value is desired, since the L value is at a compromised level by the influence of the demagnetizing field caused by the shape effect. As such applications, it is used for transmission and reception of information of RFID, which is used in a transponder of security lock systems, ID cards, tags and so on, radio control watches and radio sets. So, the frequency used in these applications is in the range of from 1 kHz and 1 MHz.
As a material having a high Q value, which is an antenna property, an amorphous metal ribbon having a composition represented by the general formula:
(Co (1−c) Fe c ) 100−a−b X a Y b
is preferable.
(In the formula, X represents at least one species of element selected from the group consisting of Si, B, C and Ge, Y represents at least one species of element selected from the group consisting of Zr, Nb, Ti, Hf, Ta, W, Cr, Mo, V, Ni, P, Al, Pt, Rh, Ru, Sn, Sb, Cu, Mn and rare earth elements, c, a and b respectively satisfy 0≦c≦0.2, 10<a≦35 and 0≦b≦30, and a and bare represented in terms of atomic %.) Although, substituting Co in the amorphous metal ribbon described above with Fe tends to increase the saturation magnetization of the amorphous metal, the smaller amount of the substitution with Fe is preferable from the view point of improving Q value. For this purpose, it is preferable that c satisfy the relationship, 0≦c≦0.2. More preferably, c satisfies the relationship, 0≦c≦0.1. The element X is an element that tends to be effective in reducing the crystallization speed for the purpose of non-crystallization in the process for producing the amorphous metal ribbon used in the present invention. If the amount of the element X is not higher than 10% by atom, it is not preferable as the non-crystallinity may deteriorate to partly contain crystalline metal. If the amount of the element X is higher than 35% by atom, it is not also preferable as the mechanical strength of the alloy ribbon may deteriorate, although amorphous structure can be obtained, and continuous ribbon may be difficult to be obtained. Therefore the amount of a, in other word, the amount of the element X, is preferably in the range of 10<a≦35, and more preferably is in the range of 12≦a≦30. The element Y tends to be effective in improving the corrosion resistance of the amorphous metal ribbon used in the present invention. The most effective elements among those are, Zr, Nb, Ti, Hf, Ta, W, Cr, Mo, V, Ni, P, Al, Pt, Rh, Ru, Sn, Sb, Cu, Mn an rare earth elements. If the added amount of the element Y is 30% or more, it is not preferable as it may occur that the ribbon becomes mechanically brittle, although it is effective in improving corrosion resistance. Therefore, it is preferable that 0≦b≦30. More preferable range is 0≦b≦20.
The magnetic substrates are laminated in an appropriate number of layers and used as a laminate. Each layer of the laminate can be the same type of magnetic substrate, or can be the different type of magnetic substrate.
The laminate is for example, press-punched out to form the shape of an antenna core in advance, and then used as a core. The one laminated after being processed by cutting or so on can be used, and the one processed to form the shape of a core by means of electric-discharge wire cutting, laser cutting processing, press punching, cutting using a rotary blade and so on after the laminate having an opportune shape is formed.
(Electric Motor)
In one aspect of the laminate of magnetic substrates of the present invention, it can be made to have an iron loss, W10/1000, defined in JIS C2550 of 15 W/kg or less, preferably 10 W/kg or less, a maximum magnetic flux density, Bs, of not less than 1.0 T and not more than 2.0 T, a tensile strength defined in JIS Z2241 of 500 MPa or more, more preferably 700 MPa or more and a relative magnetic permeability of 1,500 or more, preferably 2,500 or more. Such a material can be used in a rotor or a stator of an electric motor.
As a concrete example, the magnetic laminate of the present invention can be prepared by combining the following steps of from 1 to 5. More practically, the magnetic laminate can be prepared using the combination pattern 1 or the combination pattern 2.
Step 1: Step of preparing a magnetic substrate
Step 2: Step of processing for shape-forming
Step 3: Step of stacking
Step 4: Step of unification of laminate.
Step 5: Pressurized heat treatment using a press
Pattern 1: Step 1-Step 2-Step 3-Step 4-Step 5 (lamination is carried out after punching out the magnetic substrates) and Pattern 1: Step 1-Step 2-Step 3-Step 4-Step 2-Step 5 (punching out is carried out after the unification of the laminate) are practically preferable.
In the pattern 1, a resin is applied on an amorphous metal in the step of preparing a magnetic substrate (Step 1), the substrate is punched out in an intended shape in the step of processing for shape-forming (Step 2), and after Step 3 (step of stacking) and step 4 (step of unification of laminate), heat treatment for the purpose of improving magnetic properties are carried out in the pressurized heat treatment step using a press of Step 5.
Step 2 can be carried out only once after Step 1 as in Pattern 1, or the shape-forming of Step 2 can be carried out after a laminate is formed by carrying out the steps till Step 4 as in Pattern 2.
The steps will be explained below.
Step 1 (Step of Preparing a Magnetic Substrate)
The magnetic substrate of the present invention can be prepared according to the method, wherein a coating of liquid resin is formed on an amorphous metal ribbon from a web-roll of the amorphous metal ribbon using a coating facility such as a roll coater, and it is dried to form a heat resistant resin layer on the amorphous metal ribbon.
Step 2 (Step of Processing for Shape-Forming)
The step of processing for shape-forming of the present invention is defined as a processing, wherein a sheet or two or more sheets of the magnetic substrate(s) or the magnetic laminate is cut in the direction of the width to obtain a rectangular plate or a plate having the intended shape. The method for the processing for shape-forming in the step is selected from shearing off, punching out using a mold, photo-etching, punching out, a laser cutting, an electric-discharge wire cutting and so on. Shearing off is preferable for cutting in the direction of the width, and punching out using a mold is preferable for the cutting to obtain an intended arbitrary shape.
Step 3 (Step of Stacking)
Then, two or more sheets of the magnetic substrates processed to have rectangular or the intended shape is stacked in the direction of the thickness.
Step 4 (Step of Unification of Laminate)
As the method for the unification of the laminate of two or more sheets of the magnetic substrates, a method for unification of laminate, wherein the resin layer is melted using a heat press or a heat roll to adhere the interlayer between the metals, a method for unification of laminate, wherein swaging is carried out using a press, and a method, wherein the edge facet of the laminate is fusion bonded by laser heating to unify the laminate and so on can be used.
From the view point of realizing a material having a low magnetic loss by reducing the eddy-current loss caused by electric conduction between the layers, a method for unification of laminate by pressurizing and heating using a heat press or a heat roll is preferable. Stacked magnetic substrates of intended number are sandwiched with two sheets of metal flat plate. Although the temperature in the step of pressurizing varies depending on the types of the heat resistant resin layer formed on the amorphous metal ribbon, it is generally preferable to pressurize at a temperature around the temperature, which is higher than the glass transition temperature of the cured heat resistant resin and is where the resin is softened or turns to have a molten fluidity, to unify the amorphous metal ribbons to each other to form a laminate. After the resin of the interlayer between the amorphous metals are melted, amorphous metal ribbons are adhered to each other and unified by being cooled to the room temperature.
Step 5 (Pressurized Heat Treatment)
In order to relax the internal stress in the amorphous metal and elicit excellent magnetic properties, a heat treatment at from 300° C. to 500° C., which is necessary to elicit magnetic properties of the amorphous metal, is usually carried out on the laminate of magnetic substrates, which have been subjected to the step