WO2002080202A1

WO2002080202A1 - Composite magnetic material

Info

Publication number: WO2002080202A1
Application number: PCT/JP2001/007516
Authority: WO
Inventors: Yoshiyuki Shimada
Original assignee: Sumitomo Electric Industries, Ltd.; Denso Corporation
Priority date: 2001-03-29
Filing date: 2001-08-31
Publication date: 2002-10-10
Also published as: JPWO2002080202A1

Abstract

A composite magnetic material (1) comprising a plurality of composite magnetic particles (30) bonded to each other with an organic substance (40). The composite magnetic particle (30) includes a metallic magnetic particle (10) and a coating layer (20) bonded to the surface of the metallic magnetic particle (10) and containing a metal oxide or a metallic oxide magnetic substance. The organic substance (40) has a long-term heat-resisting temperature of 200 ° or higher. The organic substance (40) contains at least one kind selected from the group consisting of a thermoplastic resin having a ketone group, a thermoplastic polyether nitrile resin, a thermoplastic polyamide-imide resin, a thermosetting polyamide-imide resin, a thermoplastic polyimide resin, a thermosetting polyimide resin, a polyarylate resin, and a resin having fluoride.

Description

Description Composite magnetic material Technical field

The present invention relates to a composite magnetic material, and more particularly to a composite magnetic material provided with composite magnetic particles having gold magnetic particles and a layer containing metal oxide or a metal oxide magnetic substance. Background art

In recent years, with the tightening of global environmental regulations, each automaker * has been actively developing developments that reduce exhaust gas emissions and fuel consumption. For this reason, the mechanical control mechanism of the conventional engine is shifting to an electronic control mechanism, and accordingly, there is a demand for higher performance and smaller size of a magnetic material which is a central part of the control mechanism. In particular, the development of materials with high magnetic properties in the mid- and high-frequency ranges is being pursued so that more precise control can be performed with low power.

In order to have high magnetic properties in the mid-high frequency range, materials must have high saturation magnetic flux density, high magnetic permeability, and high electrical resistivity. In general, the metal magnetic material has a high saturation magnetic flux density and magnetic permeability, has a low electrical resistivity ^{(1 0- 6 ~ I 0 Ω} cm), a large eddy current loss in middle and high frequency range. As a result, the magnetic properties deteriorate, and it is difficult to use it alone.

Further, since the metal oxide magnetic material has a higher electrical resistivity than the magnetic metal material ^{(1~ 1 0 8 Ω cm)} , a small eddy current loss in middle and high frequency range, the deterioration of the magnetic properties Sukunashi. However, since the saturation magnetic flux density is 1 to 3 to 1/2 of that of metallic magnetic materials, there are limitations on applications.

In view of this situation, by combining a metal magnetic material and a metal oxide magnetic material, a composite having a high saturation magnetic flux density, a high magnetic permeability, and a high electrical resistivity, which compensates for the disadvantages of both. Magnetic materials have been proposed,

For example, in Japanese Patent Application Publication No. Hei 10-5303807, the surface of iron powder is coated with iron phosphate. There is disclosed a method of forming a composite magnetic material by joining a plurality of composite magnetic particles having a film formed thereon with an organic substance such as polyphenylene ether or polyetherimide and an amide type oligomer.

When a composite magnetic material is used in the control mechanism of an automobile engine, not only the magnetic properties described above but also the temperature of the engine becomes high, so the composite magnetic material is required to have heat resistance. However, in the composite magnetic material described in the above publication, the composite magnetic particles are bonded with an organic material having low heat resistance such as polyphenylene ether or polyetherimide and an amide type oligomer. Softens. As a result, there has been a problem that the bonding strength between adjacent composite magnetic particles is reduced, and the strength of the composite magnetic material is reduced.

Then, this invention is made in order to solve the above-mentioned problems, and an object of this invention is to provide a composite magnetic material with high heat resistance. Disclosure of the invention

The present inventors have conducted various studies on a technology for improving the heat resistance of a composite magnetic material, and found that by setting the long-term heat resistance of the organic material joining the composite magnetic particles to 200 or more, the composite magnetic material was improved. We have found that it is possible to improve the heat resistance of materials. In this specification, the term `` long-term heat-resistant temperature '' is the heat-resistant temperature specified in UL (Underwriters Laboratories) Standard 746B, and the mechanical properties of the material after long-term heat treatment in zero gravity are reduced. It is a scale indicating the heat resistance limit. Specifically, it refers to a temperature at which the properties at room temperature, such as tensile strength and impact strength, are reduced by half after heat treatment in air for 100,000 hours. For estimating the long-term heat resistance temperature, an Alewuse plot of the high temperature accelerated test is used.

The composite magnetic material according to the present invention, which has been made based on such findings, includes a plurality of composite magnetic particles joined to each other by an organic material. The composite magnetic particles have metal magnetic particles and a coating layer containing a metal oxide or a metal oxide magnetic substance bonded to the surface of the metal magnetic particles, and the organic material has a long-term temperature of 200 ° C. or more. Has heat resistant temperature. In the composite magnetic material thus configured, the plurality of composite magnetic particles are bonded to each other by an organic substance having a long-term heat-resistant temperature of 200 ° C. or more. Therefore, high Organic matter does not soften even at warm temperatures. As a result, the bonding force between the overlapping composite magnetic particles is maintained, so that the heat resistance of the composite magnetic material can be improved.

Preferably, the organic substance is a thermoplastic resin having a ketone group, a thermoplastic polyethernitrile resin, a thermoplastic polyamide resin, a thermosetting polyamide resin, a thermoplastic polyimide resin, a thermosetting polyimide resin, a polyarylate. It includes at least one selected from the group consisting of a resin and a resin having fluorine.

Polyetheretherketone (long-term heat resistance: 260 ° C), polyetherketoneketone (PEKK, long-term heatproof temperature: 240 ° C), polyetherketone (PEK, long-term) Heat resistant temperature 220 ° C) and polyketone sulfide (PKS, long-term heat resistant temperature 210-240 ° C).

Thermoplastic polyamide Doimi de, there is Amoko Ltd. trade name TOR LON (long Heat resistance temperature ^{2 30 D C~ 2 50 ° C} ) or Toray trade name TI 5000 (long-term heat resistance temperature 2 50 ° or more C) .

Polyarylate is ekonol (product name, long-term heat resistance: 240 ° C to 260 ° C).

As a thermosetting polyamide imide, there is a trade name T I 1000 (prolonged heat resistance temperature 230.C) manufactured by Toray.

Examples of fluorine-containing resins include polytetrafluoroethylene (PTFE, long-term heat resistance of 260 ° C) and tetrafluoroethylene-perfluoroalkylbierether copolymer (PFA, long-term heat resistance of 260 ° C). C) and tetrafluoroethylene-hexafluoro Q propylene copolymer (FEP, long-term heat resistance 200 ° C). Also preferably, the thickness of the coating layer is from 0.005 μm to 20 μm. If the thickness of the covering layer is less than 0.005 / 7. Nr, it will be difficult to obtain insulative properties by the covering layer. When the thickness of the coating layer exceeds 20 inches, the volume ratio of the metal oxide or metal oxide magnetic substance per unit volume increases, and it is difficult to obtain a predetermined saturation magnetic flux intensity. The thickness of the coating layer is particularly preferably from 0.0 μm to 5 μm.

More preferably, the thickness of the coating layer is not less than 0.05 μm and not more than 0.1 μrn. Preferably, the metal oxide magnetic material is Magunetai bets (F e ₂ 〇 _3), manganese (Mn) mono-zinc (Zn) ferrite, nickel (N i) —zinc (Zn) ferrite, kono noreto (Co) ferrite, manganese (Mn) ferrite, nickelo (Ni) ferrite, copper (Cu) ferrite, magnesium (Mg) ferrite, lithium (Li) ferrite, manganese (Mn) —magnesium (Mg) ferrite, copper (Cu) —zinc (Zn) ferrite and manganese (Mg) ) —Zinc (Zn) at least one species selected from the group consisting of ferrite.

Preferably, the metal oxide magnetic substance contains metal oxide magnetic particles, and the average particle diameter of the metal oxide magnetic particles is 0.005 μm or more and 5 μm or less. If the average particle diameter of the metal oxide magnetic particles is less than 0.005 μm, it becomes difficult to produce the metal oxide magnetic particles. On the other hand, if the average particle size of the gold oxide magnetic particles exceeds 5 m, it is difficult to make the thickness of the coating layer uniform. The average particle size of the metal oxide magnetic particles is particularly preferably 0.5 / .ra or more and 2 μπι or less. In this specification, “average particle size” refers to the particle size of a particle whose sum of masses from the smaller particle size reaches 50% of the total mass in a histogram of the particle size measured by the sieving method. That is, the _c- metal oxide magnetic particles having a 50% particle diameter D50 have a soft magnetic property and an electric resistivity of L 0 to ³ Ωcm or more. As described above, various soft magnetic ferrites or iron nitrides can be used. Particularly, manganese-zinc ferrite or nickel-zinc ferrite having a high saturation magnetic flux density is preferable. Use one or two or more of these.

Preferably, the metal oxide is an oxide containing phosphorus (P) and iron (F e). By using such a metal oxide, the coating layer covering the surface of the metal magnetic particles can be made thinner. Therefore, the density of the composite magnetic material can be increased, and the magnetic properties are improved.

Preferably, the average particle size of the metal magnetic particles is 5 μm or more and 200 μm or less. If the average particle size of the gold magnetic particles is less than 5 am, the metal will be oxidized and the magnetic properties will deteriorate. If the average particle size of the metal magnetic particles exceeds 200 μm, the compressibility during molding is reduced, so that the density of the molded body is reduced and it is difficult to remove it.

Preferably, the magnetic metal particles include iron CF e), iron (F e) —silicon (S i) -based alloy, iron (F e) —nitrogen (N) -based alloy, and iron (F e) —nickel (N i ) Based alloy, Iron (F e) —Carbon (C) based alloy, Iron (F e) —Boron (B) based alloy, Iron (F e) —Cobanoleto (C o) based alloy, Iron (F e) —Lin (P ) -Based alloys, iron (F e)-nickel (Ni)-cobalt (Co) based alloys and iron (Fe)-aluminum (A).)-Silicon (Si) based alloys Including at least one selected from One or more of these may be used. As long as the material of the metal magnetic particles is a soft magnetic metal, it may be a simple metal or an alloy, and there is no particular limitation.

Preferably, the ratio of the organic substance to the composite magnetic particles is from 0.05% to 2% by mass. More preferably, the ratio of the organic substance to the composite magnetic particles is from 0.1% to 1% by mass.

Preferably, 1 2 000 flux density at the time of applying a magnetic field above Arufazetapaiiota B is not less 1 5 k G or more, the electrical resistivity p force; 1 0 - no more than ³ Omega cm least 1 0 ² Omega cm, temperature Flexural strength at 200 ° C is 10 OMPa or more.

The mass ratio of the metal oxide or the metal oxide magnetic substance to the metal magnetic particles is desirably 0.2 ° / ₀ or more and 30% or less. That is, (mass of metal oxide or metal oxide magnetic substance) / (mass of metal magnetic particles) is desirably 0.2% or more and 30% or less. If the ratio is less than 0.2%, the electric resistivity decreases, which causes a decrease in AC magnetic characteristics. On the other hand, if the ratio exceeds 30%, the ratio of the metal oxide or the metal oxide magnetic material increases, and the saturation magnetic flux density decreases. More preferably, the ratio of the metal oxide or the metal oxide magnetic substance to the metal magnetic particles is preferably not less than 0.4% and not more than 0.0% by mass.

Since the composite magnetic material according to the present invention has both high magnetic properties and high heat resistance, electronic components such as choke coils, switching power supply elements and magnetic heads, various motor components, automotive solenoids, various magnetic sensors, various types Used for solenoid valves. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a sectional view of a composite magnetic material according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION (Example ]. )

As composite magnetic particles, Somaroy 500 (trade name, manufactured by Heganess Co., Ltd.) was prepared. In this powder, a coating layer made of a metal oxide containing phosphorus and iron is formed on the surface of gold dust and iron powder as magnetic particles. The average particle size of the composite magnetic particles is 150 μη · ι or less, and the average thickness of the coating layer is 20 nHi.

The composite magnetic particles, so that the mass ratio of 1% 0., the average particle size of _u this particles were prepared particles Porieterue Ichite ketone resin is less 3 mu m.

These were mixed in a ball mill to form a mixed powder. There is no particular limitation on the mixing method. For example, mechanical alloying, vibrating ball mill, planetary ball mill, mechanofusion, coprecipitation, chemical vapor deposition (CVD), physical vapor deposition

(PVD method), plating method, sputtering method, evaporation method, sol-gel method, etc. can be used.

The mixed powder was placed in a mold and molded. As a molding method, a mold lubrication molding in which a lubricant was applied to a mold to perform molding was used. The temperature of the mold was 130 ° C, the temperature of the mixed powder was 130 ° C, and the molding pressure was 784 MPa to form a compact. The temperature of the mold can be from 70 C to 150 ° C, the temperature of the mixed powder can be 200 from room temperature, and the molding pressure can be from 392 MPa to 98 OMPa.

The molded body was heat-treated (annealed) at a temperature of 420 ° C in a nitrogen gas atmosphere. As a result, the polyetheretherketone softened and entered the interface between the plurality of composite magnetic particles to join the composite magnetic particles to obtain a solid. Note that the temperature of the heat treatment is preferably in the range of 340 ° C to 450 ° C. At temperatures below 340 ° C, the polyetheretherketone does not soften completely and does not diffuse uniformly. If the temperature is 450 ° C or higher, the strength of the composite magnetic material does not improve due to decomposition of the polyetheretherketone. In addition, when heat treatment is performed in the atmosphere, polyether ether ketone gels and the strength of the composite magnetic material deteriorates. Heat treatment in argon or helium increases manufacturing costs. Note that, as the heat treatment, HP (HotIssostaticPRessinng), SPS (SparkPlassaSintering), or the like can be used.

Finally, the solid was processed to obtain a composite magnetic material. FIG. 1 shows a composite according to the invention. It is sectional drawing of a magnetic forest material. Referring to FIG. 1, composite magnetic material 1 includes a plurality of composite magnetic particles 30 joined to each other by organic substance 40. The composite magnetic particles 30 include metal magnetic particles 10 and a coating layer 20 containing a metal oxide or a metal oxide magnetic substance, which is bonded to the surface of the metal magnetic particles 10. Organic substance 40 has a long-term heat-resistant temperature of 200 ° C. or higher. The density of this composite magnetic material 1 was 7.55 g Zc. The magnetic flux density when a magnetic field of 1200 Am was applied was 17 kG, and the electric resistivity p was 100 Ωcm.

Further, the composite magnetic material 1 was machined into a prism shape having a length, width, and thickness of 1 Omm X 5 Omm X 1.0 mm. When a three-point bending test was performed at room temperature with a span of 40 mm, the transverse rupture strength was] .5 OMPa. When a three-point bending test was performed at a temperature of 200 ° C. with a span of 4 O mm, the transverse rupture strength was 13 OMPa. In the present invention, since the long-term heat resistance of polyetheretherketone is 200 ° C. or higher, the strength at high temperatures is increased, and the heat resistance of composite magnetic material 1 is improved. Furthermore, polyetheretherketone has a low viscosity (melt viscosity) when softened, so even a small amount of the polyetheretherketone causes a uniform capillary phenomenon. In addition, since the composite magnetic particles 1 can be surely joined to each other with a small amount, the amount of organic substances can be reduced. As a result, the ratio of the metal magnetic material 10 can be increased, and the magnetic characteristics can be improved.

Further, the use of the metal mold molding can reduce the amount of lubricant in the molded body. As a result, the density of one composite magnetic material is improved, and the magnetic properties can be improved. Further, since it is possible to prevent the occurrence of voids inside the molded body, it is possible to improve the magnetic permeability.

(Examples 2 and 3.)

In Examples 2 and 3, a composite magnetic material was obtained by the same manufacturing method as in Example 1 except that the average thickness of the coating layer in Example 1 was set to 511 m and 100 nm. The density, the magnetic flux density when a magnetic field of 1200 AZm was applied, and the electrical resistivity of the obtained composite magnetic material compact were measured. Further, the composite magnetic material was machined into a square main shape having a length, width, and thickness of 10 mm × 50 mm × 10 mm. Flexural strength when performing a three-point bending test at room temperature with a span of 40 mm. The bending strength at the time of performing a three-point bending test at a temperature of 200 ° C was measured. Table 1 shows the results.

table 1.

Table 1 shows that the electrical resistivity is higher than that of Example 1. Therefore, when it is desired to improve the electric resistivity, it is preferable that the average thickness of the coating layer is not less than 50 ηηι and not more than 100 nm.

(Comparative example)

As composite magnetic particles, Somaroy 500 (trade name, manufactured by Heganess Co., Ltd.) was prepared. In this powder, a coating layer made of a metal oxide containing phosphorus and iron is formed on the surface of iron powder as magnetic metal particles. The average particle size of the composite magnetic particles is 150 μm or less, and the average thickness of the coating layer is 20 nm.

Amid-type oligomer particles were mixed so that the mass ratio to the composite magnetic particles was 0.6%.

The mixed powder was placed in a mold, compressed at room temperature at a pressure of 60 OMPa, and then heat-treated in the atmosphere at a temperature of 300 ° C for 60 minutes. Thus, a composite magnetic material was obtained.

The density of this composite magnetic material was 7.15 g cm ³ . When a magnetic field of 12000 A Zm was applied, the magnetic flux density was 15 kG, and the electric resistivity p was 2 Ωcm. Further, the composite magnetic material was machined into a prism shape having a length, width, and thickness of 1 OmmX5OmmX10 mm. When a three-point bending test was performed at room temperature with a span of 4 Omin, the transverse rupture strength was 12 OMPa. When a three-point bending test was performed at a temperature of 200 ° C with a span of 4 Omm, the transverse rupture strength was 1 OMPa.

Although the embodiments of the present invention have been described above, the embodiments shown here can be variously modified.

First, in the above embodiment, the coating layer was formed of an oxide containing phosphorus and iron. Even if the coating layer was formed of metal oxide magnetic particles, the same effect as in the above embodiment was obtained. Can be obtained. In this case, it is necessary to mix the metal magnetic particles and the metal oxide magnetic particles. There is no particular limitation on the method of mixing the metal magnetic particles and the metal oxide magnetic particles, such as a mechanical two-way lubricating method, a ball mill, a vibrating ball mill, a planetary ball mill, a mechanofusion, a coprecipitation method, and a chemical vapor deposition method. It is possible to use any of (CVD method), physical vapor deposition method (PVD method), plating method, sputtering method, vapor deposition method, and sol-gel method.

The embodiments disclosed this time should be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

According to the present invention, a composite magnetic material having high heat resistance can be obtained. Industrial availability

The composite magnetic material according to the present invention is used for electronic components such as choke coils, switching power supply elements, and magnetic heads, various motor components, automotive solenoids, various magnetic sensors, various solenoid valves, and the like.

Claims

Claims I. A plurality of composite magnetic particles (30) joined to each other by an organic substance (40), wherein the composite magnetic particles (30) are metal magnetic particles (10), and the metal magnetic particles (1 0), and a coating layer (20) containing a metal oxide or a metal oxide magnetic substance,

'The organic substance (40) has a long-term heat resistance of 2 ° 0 ° C or higher, a composite magnetic material:>

2. The organic substance (40) is a thermoplastic resin having a ketone group, a thermoplastic polyester ternitrile resin, a thermoplastic polyamide imide resin, a thermosetting polyamide imide resin, a thermoplastic polyimide resin, a thermosetting polyimide resin. The composite magnetic material according to claim 1, which comprises at least one member selected from the group consisting of a polyarylate resin and a resin having fluorine.

3. The composite magnetic material according to claim 1, wherein the thickness of the coating layer (20) is from 0.005 μπι to 20 μπι.

4. The composite magnetic material according to claim 3, wherein the thickness of the coating layer (20) is 0.05 to 111.

5. The metal oxide magnetic material is magnetite, manganese-zinc fluoride, nickel zinc ferrite, cobalt ferrite, manganese ferrite, nickel ferrite, copper ferrite, magnesium ferrite, lithium ferrite, manganese ferrite. 2. The composite magnetic material according to claim 1, comprising at least one selected from the group consisting of magnesium ferrite, copper-zinc ferrite, and manganese-zinc ferrite.

6. The composite magnetic forest material according to claim 1, wherein the metal oxide comprises an oxide containing iron and phosphorus.

7. The average particle size of the metal magnetic particle (1 0) is 200 _M m below 5 Myupaiiota above, the composite magnetic material according to claim 1.

8. The magnetic metal particles (10) are iron, iron-silicon alloy, iron-nitrogen alloy, iron-nickel alloy, iron-carbon alloy, iron-boron alloy, iron-cobalt alloy. , 2. The composite magnetic material according to claim 1, comprising at least one selected from the group consisting of iron-phosphorus alloys, iron-nickel-cobalt alloys, and iron-aluminum silicon alloys.

9. The composite magnetic material according to claim 1, wherein a ratio of the organic substance (40) to the composite magnetic particles (30) is 0.05% to 2% by mass.

10.1200 an OA Roh m or more magnetic flux density B at the time of applying a magnetic field on the 15 k G than the electrical resistivity p force; or less 10- ³ Ω c πι least 10 ² Omega cm, temperature 20 0 2. The composite magnetic material according to claim 1, having a flexural strength at 10 ° C. of 10 OMPa or more.