ALLOY POWDER COMPOSITION, MOLDING AND THE MANUFACTURING METHOD THEREOF, AND INDUCTORS

Abstract

The present application relates to an alloy powder composition, a method for manufacturing a molding from the alloy powder composition, a molding obtained from the method, and an inductor comprising the molding. The alloy powder composition comprises an Fe-based amorphous alloy powder and an Fe-based crystalline alloy powder; wherein the Fe-based amorphous alloy powder has a volume resistivity of equal to or less than 110.sup.6 .Math.cm when subjected to a force of 20 kN and the Fe-based crystalline alloy powder has a volume resistivity of equal to or greater than 110.sup.6 .Math.cm when subjected to a force of 20 kN; and wherein the Fe-based amorphous alloy powder comprises Fe, Co, Cr, C, P, and Si.

Claims

1. Alloy powder composition comprising an Fe-based amorphous alloy powder and an Fe-based crystalline alloy powder, wherein the Fe-based amorphous alloy powder has a volume resistivity of 110.sup.6 .Math.cm or less when subjected to a force of 20 kN, and the Fe-based crystalline alloy powder has a volume resistivity of 110.sup.6 .Math.cm or more when subjected to a force of 20 kN; and wherein the Fe-based amorphous alloy comprises Fe, Co, Cr, C, P, and Si, and optionally one or more of Ni, B, and Al.

2. The alloy powder composition of claim 1, wherein the Fe-based amorphous alloy comprises the following atomic ratios: 70 at %<Fe<83 at %; 0 at %<Co<1 at %; 1 at %<Cr<4 at %; 7 at %<C<11 at %; 9 at %<P<12 at %; 0 at %<Si<1 at %; Ni being absent or 5 at %<Ni<7 at %; 0 at %B<3 at %; and 0 at %Al<1 at %.

3. The alloy powder composition of claim 1, wherein the Fe-based amorphous alloy comprises the atomic ratio of 70 at %<Fe<78 at %.

4. The alloy powder composition of claim 1, wherein the oxygen content of the Fe-based amorphous alloy is equal to or less than 2500 ppm.

5. The alloy powder composition of claim 1, wherein the Fe-based crystalline alloy powder is selected from one or more of the group consisting of FeNi based alloy, FeCo based alloy, FeV based alloy, FeSiCr based alloy, FeAl based alloy, FeSi based alloy, and FeSiAl based alloy, and the Fe-based crystalline alloy powder has a median diameter D.sub.50 of from 2.5 m to 6 m.

6. The alloy powder composition of claim 5, wherein the Fe-based crystalline alloy is FeSiCr based alloy.

7. The alloy powder composition of claim 6, wherein the Cr content of the FeSiCr based alloy is equal to or greater than 4 wt %.

8. The alloy powder composition of claim 1, wherein the Fe-based amorphous alloy powder has a tap density of =3.5 g/cm.sup.3, and the Fe-based crystalline alloy powder has a tap density of 2 g/cm.sup.3.

9. The alloy powder composition of claim 1, wherein the Fe-based amorphous alloy powder has a BET specific surface area of from 0.15 m.sup.2/g to 0.30 m.sup.2/g, and the Fe-based crystalline alloy powder has a BET specific surface area of from 0.5 m.sup.2/g to 2.5 m.sup.2/g.

10. The alloy powder composition of claim 1, wherein the Fe-based amorphous alloy powder has a median diameter D.sub.50 of from 4 m to 14 m.

11. The alloy powder composition of claim 1, wherein the mixing ratio of the Fe-based amorphous alloy powder and the Fe-based crystalline alloy powder is in the range of from 20:80 to 95:5 by weight.

12. Method for manufacturing a molding, comprising mixing the alloy powder composition according to claim 1 and a binder to form a molding material, and pressure molding the molding material.

13. The method of claim 12, wherein the binder is epoxy resin, polysiloxane resin, acrylic resin, phenolic resin, or polyvinyl alcohol.

14. The method of claim 12, wherein the binder is used in an amount of from 1 wt % to 4 wt %, based on the total weight of the alloy powder composition and the binder.

15. Molding obtained by the method according to claim 12, wherein the molding has a volume resistivity of equal to or greater than 110.sup.4 .Math.cm and a relative molding density of 70% to 95%.

16. Inductor comprising the molding of claim 15.

17. The inductor of claim 16, comprising a conductor, wherein the conductor is embedded inside the molding or wound around the molding on the outside.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0013] FIG. 1 shows the relationship between permeability and frequency of the inventive Examples 1-2 and Comparative Example.

[0014] FIG. 2 shows the relationship between iron loss and frequency of the inventive Examples 1-2 and Comparative Example at B.sub.m=10 mT.

[0015] FIG. 3 shows the relationship between iron loss and frequency of the inventive Examples 1-2 and Comparative Example at B.sub.m=50 mT.

[0016] FIG. 4 shows the relationship between iron loss and frequency of the inventive Examples 1-2 and Comparative Example at B.sub.m=100 mT.

[0017] FIG. 5 shows the inductance conversion efficiency of the inventive Examples 1-2 and Comparative Example.

MODE FOR CARRYING OUT THE INVENTION

[0018] The alloy powder composition of the present invention comprises an Fe-based amorphous alloy powder and an Fe-based crystalline alloy powder; wherein the Fe-based amorphous alloy powder has a volume resistivity of equal to or less than 110.sup.6 .Math.cm when subjected to a force of 20 kN and the Fe-based crystalline alloy powder has a volume resistivity of equal to or greater than 110.sup.6 .Math.cm when subjected to a force of 20 kN; and wherein the Fe-based amorphous alloy powder comprises Fe, Co, Cr, C, P, and Si, and optionally one or more of Ni, B, and Al. According to the alloy powder composition of the present invention, the volume resistivity of the Fe-based amorphous alloy powder and the Fe-based crystalline alloy powder is determined in accordance with JIS K6911 in combination with, for example, the powder resistivity measuring system, MCP-PD51, and is the value measured under a force of 20 kN.

[0019] The Fe-based amorphous alloy of the present invention comprises Fe, Co, Cr, C, P, and Si.

[0020] In one embodiment of the present invention, the Fe-based amorphous alloy may additionally comprise one or more of Ni, B, and Al.

[0021] In one embodiment of the present invention, the Fe-based amorphous alloy comprises or consists of Fe, Co, Cr, C, P, and Si.

[0022] In one embodiment of the present invention, the Fe-based amorphous alloy comprises or consists of Fe, Co, Cr, C, P, B, and Si.

[0023] In one embodiment of the present invention, the Fe-based amorphous alloy comprises or consists of Fe, Co, Cr, C, P, Al, and Si.

[0024] In one embodiment of the present invention, the Fe-based amorphous alloy comprises or consists of Fe, Co, Ni, P, Cr, C, and Si.

[0025] In one embodiment of the present invention, the Fe-based amorphous alloy comprises or consists of Fe, Co, Ni, P, Cr, C, B, and Si.

[0026] In one embodiment of the present invention, the Fe-based amorphous alloy comprises or consists of Fe, Co, Ni, P, Cr, C, Al, and Si.

[0027] In one embodiment of the present invention, the Fe-based amorphous alloy may comprise the following atomic ratios: [0028] 70 at %<Fe<83 at %; [0029] 0 at %<Co<1 at %; [0030] 1 at %<Cr<4 at %; [0031] 7 at %<C<11 at %; [0032] 9 at %<P<12 at %; [0033] 0 at %<Si<1 at %; [0034] Ni being absent or 5 at %<Ni<7 at %; [0035] 0 at % B<3 at %; and [0036] 0 at %Al<1 at %.

[0037] In one embodiment of the present invention, the amount of Fe in the Fe-based amorphous alloy is, for example, in the range of >70 at % to <83 at %, or in the range of >70 at % to <81 at %, or in the range of >70 at % to <79 at %, or in the range of >70 at % to <78 at %.

[0038] In one embodiment of the present invention, the oxygen content of the Fe-based amorphous alloy is equal to or less than 2500 ppm, or equal to or less than 2300 ppm, or equal to or less than 2000 ppm.

[0039] In one embodiment of the present invention, the median diameter D.sub.50 of the Fe-based amorphous alloy powder is from 4 m to 14 m, or from 5 m to 12 m, determined in accordance with laser diffraction method.

[0040] The examples of the Fe-based crystalline alloy of the present invention comprise FeNi based alloy, FeCo based alloy, FeV based alloy, FeSiCr based alloy, FeAl based alloy, FeSi based alloy, and FeSiAl based alloy. These alloys can be used alone or as a mixture thereof. In the present invention, the FeSiCr based alloy is preferably used.

[0041] In one embodiment of the present invention, the Fe-based crystalline alloy powder has a median diameter D.sub.50 of from 1 m to 15 m, from 2 m to 10 m, or from 2.5 m to 6 m, determined in accordance with laser diffraction method.

[0042] In one embodiment of the present invention, the Fe-based crystalline alloy is FeSiCr based alloy.

[0043] In one preferred embodiment of the present invention, the Fe-based crystalline alloy is FeSiCr based alloy, wherein the Cr concentration thereof is equal to or greater than 4 wt %.

[0044] In one embodiment of the present invention, the Fe-based amorphous alloy powder has a tap density of 3.5 g/cm.sup.3 and the Fe-based crystalline alloy powder has a tap density of 2 g/cm.sup.3. The tap density is determined in accordance with, for example, ISO 3953, wherein the tap density is the packing density when the powder in a cylinder has been tapped for defined times and the volume of the powder is no longer changed. The Fe-based amorphous alloy powder has a BET specific surface area of from 0.15 m.sup.2/g to 0.30 m.sup.2/g and the Fe-based crystalline alloy powder has a BET specific surface area of 0.5 m.sup.2/g to 2.5 m.sup.2/g, wherein the BET specific surface area is determined according to, for example, ISO 9277.

[0045] According to the alloy powder composition of the present invention, the mixing ratio of the Fe-based amorphous alloy powder and the Fe-based crystalline alloy powder is in the range of from 20:80 to 95:5, from 30:70 to 95:5, from 40:60 to 95:5, from 50:50 to 95:5, from 60:40 to 95:5, from 70:30 to 95:5, from 80:20 to 95:5, or from 90:10 to 95:5, by weight. In a preferred embodiment of the present invention, the mixing ratio of the Fe-based amorphous alloy powder and the Fe-based crystalline alloy powder is 90:10 by weight.

[0046] The Fe-based amorphous alloy powder of the present invention may be produced, for example, by atomization. The atomization process breaks the alloy liquid into fine droplets by impact with a rapidly moving fluid (atomizing medium) or other means and then the droplets are cooled to form solid powders.

[0047] Another aspect of the present invention is a method for manufacturing a molding comprising mixing the alloy powder composition according to the present invention and a binder to form a molding material, and pressure molding the molding material to obtain a molding. The molding pressure is not limited. According to the Shin Tajima el at., Properties of High-Density Magnetic Composite (HDMC) by Warm Compaction Using Die Wall Lubrication, J. Jpn. Soc. Powder Metallurgy Vol. 50, No. 7, as the molding pressure increases, the volume resistivity decreases. Those skilled in the art can adjust the molding pressure according to the ratio of the Fe-based amorphous alloy powder added and the mechanical strength of the resulted molding to obtain a molding having a volume resistivity of 110.sup.4 .Math.cm or more. During the pressure molding process, heat can optionally be applied. Examples of the binder used in the present invention are epoxy resin, polysiloxane resin, acrylic resin, phenolic resin, or polyvinyl alcohol. The amount of the binder used in the method of the present invention is from 1 wt % to 4 wt %, or from 1 wt % to 3 wt %, or from 2 wt % to 3 wt %, based on the total weight of the alloy powder composition and the binder.

[0048] Another aspect of the present invention is a molding comprising the alloy powder composition according to the present invention, wherein the molding has a volume resistivity of 110.sup.4 .Math.cm or more and a relative molding density of 70% to 95%.

[0049] The molding of the present invention has a relative molding density of from 70% to 95%, or a relative molding density of from 75 to 92%, or a relative molding density of from 80% to 90%. The relative molding density is defined as the following formula:

[00001]$\mathrm{Relative}.Math..Math.\mathrm{Molding}.Math..Math.\mathrm{Density}.Math..Math.\left(\%\right)=\frac{\mathrm{the}.Math..Math.\mathrm{density}.Math..Math.\mathrm{of}.Math..Math.\mathrm{the}.Math..Math.\mathrm{pressure}-\mathrm{molded}.Math..Math.\mathrm{molding}}{\begin{array}{c}\mathrm{the}.Math..Math.\mathrm{true}.Math..Math.\mathrm{density}.Math..Math.\mathrm{of}.Math..Math.\mathrm{the}.Math..Math.\mathrm{alloy}\\ \mathrm{powder}.Math..Math.\mathrm{composition}.Math..Math.\mathrm{before}.Math..Math.\mathrm{molding}\end{array}}100.$

[0050] The shape of the molding of the present invention is not limited and may be, for example, an E-shape, a T-shape, or a drum-shape.

[0051] Another aspect of the present invention is an inductor comprising the molding according to the present invention and a conductor, such as a conducting wire with an insulating layer or bus bar. The inductor of the present invention may be, for example, a wire wound inductor or a molded inductor.

[0052] In one embodiment of the present invention, the inductor is a wire wound inductor, and the conducting wire with an insulating layer is wound around the molding. The wire wound inductor of the present invention is obtained by winding a conducting wire with an insulating layer on the molding of the present invention and sealing the molding by covering with a magnetic sealant from outside.

[0053] In one embodiment of the present invention, the inductor is a molded inductor, and the conductor is embedded inside the molding. The method for manufacturing the molded inductor is disclosed in U.S. Pat. No. 6,204,474 B1 and U.S. Pat. No. 6,1983,075 B1. The inductor of the present invention is manufactured, for example, by the following method: welding one end of the conductor to a lead frame; winding the conductor; welding the other end of the conductor to the lead frame; placing the conductor into a die; mixing the mixture of the alloy powder composition of the present invention and the binder to form a molding material; pouring the molding material into the die; pressuring molding; heating to cure the binder. Examples of the binder used in the present invention are epoxy resin, polysiloxane resin, acrylic resin, phenolic resin, or polyvinyl alcohol. Fillers and/or lubricants can be optionally added to the molding material. In the pressure molding step, appropriate pressure is applied to the molding material to compress the molding material around the conductor.

EXAMPLES

Example 1

[0054] The Fe-based amorphous alloy powder and the Fe-based crystalline alloy powder with the properties shown in Table 1 were used. After mixing 90 wt % of Fe.sub.77.27Co.sub.0.1P.sub.10.8C.sub.9.31Cr.sub.2Si.sub.0.52 powder and 10 wt % of Fe.sub.88.6Cr.sub.6.7Si.sub.4.7 powder, an acrylic resin was added as a binder to form a molding material. The molding material was then pressure molded under a molding pressure of 20 t/cm.sup.2 to form a molding having a volume resistivity of greater than 10.sup.4 .Math.cm and a relative molding density of 82%. The oxygen content of the Fe.sub.77.27Co.sub.0.1P.sub.10.8C.sub.9.31Cr.sub.2Si.sub.0.52 powder is 13001400 ppm, and the Cr concentration of the Fe.sub.88.6Cr.sub.6.7Si.sub.4.7 powder is 4.5 wt %. The amount of the acrylic resin binder used was 2 wt % based on the total weight of the alloy powder composition and the binder.

TABLE-US-00001 TABLE 1 The properties of the Fe-based amorphous alloy and the Fe-based crystalline alloy used in Example 1 Volume resistivity .Math. cm when Specific subjected to a Tap density surface force of 20 kN g/cm.sup.3 area m.sup.2/g Fe-based amorphous alloy 0.8 10.sup.3 4.38 0.21 Fe.sub.77.27Co.sub.0.1P.sub.10.8C.sub.9.31Cr.sub.2Si.sub.0.52 Fe-based crystalline alloy 4.5 10.sup.8 3.3 1.76 Fe.sub.88.6Cr.sub.6.7Si.sub.4.7

Example 2

[0055] The Fe-based amorphous alloy powder and the Fe-based crystalline alloy powder with the properties shown in Table 2 were used. After mixing 90 wt % of Fe.sub.70.97Co.sub.0.1Ni.sub.5.96Cr.sub.1.99P.sub.10.74C.sub.7.75B.sub.1.99Si.sub.0.5 powder and 10 wt % of Fe.sub.88.6Cr.sub.6.7Si.sub.4.7 powder, an acrylic resin was added as a binder to form a molding material. The molding material was pressure molded under a molding pressure of 20 t/cm.sup.2 to form a molding having a volume resistivity of greater than 10.sup.4 .Math.cm and a relative molding density of 82%. The oxygen content of the Fe.sub.70.97Co.sub.0.1Ni.sub.5.96Cr.sub.1.99P.sub.10.74C.sub.7.75B.sub.1.99Si.sub.0.5 powder is 13001400 ppm, and the Cr concentration of the Fe.sub.88.6Cr.sub.6.7Si.sub.4.7 powder is 4.5 wt %. The amount of the acrylic resin binder used was 2 wt % based on the total weight of the alloy powder composition and the binder.

TABLE-US-00002 TABLE 2 The properties of the Fe-based amorphous alloy and the Fe-based crystalline alloy used in Example 2 Volume resistivity .Math. cm when Specific subjected to a Tap density surface force of 20 kN g/cm.sup.3 area m.sup.2/g Fe-based amorphous alloy 0.8 10.sup.3 4.38 0.21 Fe.sub.70.97Co.sub.0.1Ni.sub.5.96Cr.sub.1.99P.sub.10.74C.sub.7.75B.sub.1.99Si.sub.0.5 Fe-based crystalline alloy 4.5 10.sup.8 3.3 1.76 Fe.sub.88.6Cr.sub.6.7Si.sub.4.7

Comparative Example

[0056] The Fe-based amorphous alloy powder and the Fe-based crystalline alloy powder with the properties shown in Table 3 were used. After mixing 30 wt % of Fe.sub.73Si.sub.11B.sub.10.8Cr.sub.23C.sub.2.9 powder and 70 wt % of carbonyl iron powder (CIP), an epoxy resin was added as a binder to form a molding material. The molding material was then pressure molded under a molding pressure of 20 t/cm.sup.2 to form a molding having a volume resistivity of greater than 10.sup.4 .Math.cm and a relative molding density of 87%. The amount of the epoxy resin binder used was 4.5 wt % based on the total weight of the alloy powder composition and the binder. It should be noted that in Comparative Example, in order to obtain the molding having a volume resistivity of greater than 10.sup.4 .Math.cm, it is required to add a higher amount of the binder, resulting in poor soft magnetic properties.

TABLE-US-00003 TABLE 3 The properties of the Fe-based amorphous alloy and the Fe-based crystalline alloy used in Comparative Example Volume resistivity .Math. cm when Specific subjected to a Tap density surface force of 20 kN g/cm.sup.3 area m.sup.2/g Fe-based amorphous alloy 0.8 10.sup.3 4.1 1.1 Fe.sub.73Si.sub.11B.sub.10.8Cr.sub.2.3C.sub.2.9 Fe-based crystalline alloy 6.5 4.7 0.77 Carbonyl iron powder

[0057] The permeability r and iron loss P.sub.CV of the moldings obtained according to Examples 1-2 and Comparative Example were measured, and the results are shown in FIG. 1 and FIGS. 2-4.

[0058] FIG. 1 shows the relationship between permeability and frequency. The permeability r shown in FIG. 1 is the real part of relative permeability, which is the real part of relative permeability measured by using a magnetic ring with an outer diameter of 13.5 mm, an inner diameter of 7.6 mm, and a height of 5 mm made of the molding materials of Examples 1-2 and Comparative Example, respectively. It can be seen from FIG. 1 that the permeability of the moldings of Examples 1-2 is much higher than that of Comparative Example, and the moldings have stable permeability even in the high-frequency region. FIGS. 2-4 exhibit the relationship between iron loss and frequency under different maximum magnetic flux densities (B.sub.m=10, 50, and 100 mT). The moldings of Examples 1-2 both have a significantly lower iron loss.

[0059] The inductance conversion efficiency was further analyzed and the results are shown in FIG. 5. As can be seen from FIG. 5, the conversion efficiency of the inductors obtained from the moldings of Examples 1-2 is remarkably superior to that of Comparative Example.

[0060] Although the preferred embodiments of the present invention have been described in detail above with reference to the drawings, the invention is not limited to the embodiments described above. A person having ordinary skill in the art can make various changes within the scope of the claims and can also arbitrarily combine various embodiments disclosed in the specification, and it is obvious that these also belong to the technical scope of the present invention.