JPH06158110A - Production of sintered compact of soft magnetic fe-co-v-p alloy material - Google Patents

Abstract

PURPOSE:To produce a sintered compact of an Fe-Co-V-P alloy material having excellent soft magnetic characteristics. CONSTITUTION:A compsn. consisting of a binder and powder having <=45mum average particle diameter so blended that it consists of 40-60wt.% Co, 0.3-3wt.% V, 0.1-1wt.% P and the balance essentially Fe is injection-molded and the resulting molded body is freed of the binder and sintered in the temp. range of 1,100-1,450 deg.C. The resulting sintered compact is slowly cooled at 2-50 deg.C/min cooling rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to F which is excellent in soft magnetic characteristics.
The present invention relates to a method for manufacturing an e-Co-VP alloy soft magnetic material sintered body.

[0002]

2. Description of the Related Art Fe-Co alloy soft magnetic materials have a rule-
It is an alloy material that undergoes disordered transformation and forms a CsCl-type ordered lattice phase at the transformation temperature. Since it has the highest saturation magnetic flux density among currently known alloys, it is magnetic for yokes of pulse motors, printer heads, etc. Widely used as a diaphragm for materials and receivers. However, if it is made of only Fe and Co, no matter what heat treatment is performed,
The transformation from disordered lattice to ordered lattice could not be suppressed, so cold working was impossible.

Therefore, in order to improve such a situation, an Fe-Co-V alloy in which V is added to improve workability is more practically used than the Fe-Co alloy. However, it is still not sufficient to suppress the transformation into a regular lattice, and attempts have been made to manufacture by a powder metallurgy method in order to obtain a molded product, particularly a component having a complicated shape. On the other hand, the usual powder metallurgy method involves inserting raw material powder into a mold and performing compression molding by pressing. Since Co powder and Fe-Co alloy powder are hard, a large pressure is applied during compression molding. However, it is difficult to mold and cracks easily occur. Further, in this case, a raw material powder having a relatively large average particle size is used, and since Fe and Co are hard to diffuse into each other, it is difficult to increase the density to obtain magnetic characteristics, and expensive fine powder is used to increase the density. , Long-term sintering and HIP treatment must be performed. Further, after sintering, it is always necessary to perform heat treatment for improving magnetic properties. Further, when it is used as an alternating current as a soft magnetic material, it has a large electric resistance and it is necessary to reduce iron loss.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional drawbacks and to produce an Fe-Co-VP alloy material sintered body having excellent soft magnetic characteristics. It is to provide a method that can.

[0005]

As a result of research to solve the above-mentioned problems, the present inventor has blended powders having a specific particle size so as to have a specific composition, and injection-molded the resulting molded product. After the binder treatment and further the sintering treatment, by gradually cooling at a specific cooling rate, the generation of lattice strain generated during cooling is controlled, and the above-mentioned problems can be solved without lowering the magnetic properties of the product. It has been found that a higher density and higher electric resistance can be achieved to obtain a certain magnetic property.

That is, in the method for manufacturing the Fe-Co-VP alloy soft magnetic material sintered body of the present invention, Co is 40 to 60% by weight, V is 0.3 to 3% by weight and P is 0.1 to 0.1% by weight. A composition comprising 1% by weight and a powder having a mean particle size of 45 μm or less and a binder, which is blended so that the balance substantially consists of Fe, is injection-molded, and the obtained molded body is subjected to a binder removal treatment. It is characterized in that after performing the sintering treatment in the temperature range of ˜1450 ° C., the sintered body is gradually cooled at a cooling rate of 2˜50 ° C./min.

[0007]

The Co content of the blended powder and the sintered body after sintering must be 40 to 60% by weight. When the Co content is less than 40% by weight, the magnetic flux density does not decrease so much, but the maximum magnetic permeability greatly decreases, and it cannot be used as a soft magnetic material. Even when the Co content exceeds 40% by weight, the magnetic flux density does not decrease so much, but the maximum magnetic permeability greatly decreases, and it cannot be used as a soft magnetic material.

The V content must be 0.3 to 3% by weight. If the V content is less than 0.3% by weight, the electric resistance is not improved. If the V content exceeds 3% by weight, the magnetic flux density decreases sharply, and it cannot be used as a soft magnetic material.

Further, the P content must be 0.1 to 1% by weight. If the P content is less than 0.1% by weight, the final relative density after sintering is hardly improved, and as a result, not only the excellent soft magnetic characteristics are exhibited, but also the electric resistance is not improved. When the P content exceeds 1% by weight, the magnetic flux density is drastically reduced, and it cannot be used as a soft magnetic material.

Co, V, P and Fe are the respective powders, or Fe-Co-V alloy powder, Fe-Co alloy powder,
Fe-V alloy powder, Fe-P alloy powder, or the like may be used as appropriate. It is desirable that the sintered body does not contain elements other than Fe, Co, V, and P, but if the magnetic flux density of the soft magnetic characteristics of the sintered body does not fall below B ₃₅ = 19000 G, it is included. It does not matter if you

The average particle size of this powder must be 45 μm or less. If the average particle size exceeds 45 μm, the fluidity of the composition comprising the powder and the binder decreases, making injection molding almost impossible.
Even if injection molding is possible, the progress of the process of sintering the molded body is delayed. Therefore, the final density of the sintered body is unlikely to increase, and the magnetic properties are significantly reduced.

As the binder in the present invention, known binders for injection molding powder metallurgy, such as polyethylene and wax, can be used, but residual carbon is generated when the binder is removed, and Fe--Co--
When carbon penetrates into the VP alloy, the magnetic properties deteriorate, so it is preferable to use a binder in which carbon is unlikely to remain, for example, a binder mainly composed of wax.

As a method of removing the binder from the molded body, heating degreasing, depending on the kind of the binder used,
Although solvent degreasing and other known methods can be used, the heat degreasing apparatus is preferably a heat degreasing apparatus that is performed in a nitrogen or hydrogen atmosphere or in a vacuum during mass production because the heat degreasing apparatus is simpler than the apparatuses of other methods. When the debindered molded body is sintered, it is held at 1100 to 1450 ° C. in a hydrogen atmosphere or in vacuum for 30 to 300 minutes. At this time, the molded body may be inserted into a furnace that has been heated in advance, or the molded body may be inserted into the furnace at room temperature and then heated at an appropriate heating rate.

The sintered product, which has been subjected to the sintering work in this manner, is then required to be gradually cooled at a cooling rate of 2 to 50 ° C./min. Gradually cooling at a cooling rate of less than 2 ° C./min is not preferable because not only the effect of the present invention for removing lattice strain cannot be improved but also productivity is significantly reduced. Further, when the cooling rate exceeds 50 ° C./min, lattice distortion occurs during cooling and remains at room temperature as it is, so that the soft magnetic characteristics deteriorate.

[0015]

【Example】

Examples 1 to 8 and Comparative Examples 1 to 10 Fe-50 wt% Co alloy powder having an average particle size of 9 μm, Fe-53 wt% V alloy powder having an average particle size of 40 μm as raw material powders,
Fe-27% by weight P alloy powder having an average particle size of 40 μm, carbonyl Fe powder having an average particle size of 5 μm, and reduced Co powder having an average particle size of 4.5 μm were used at the compounding ratios shown in Table 1. After that, they are mixed, and a wax-based binder is added to this so that the binder content is 40 to 50% by volume.
After kneading at 50 ° C, the mixture was granulated into pellets. The pellets were injected using an injection molding machine at an injection pressure of 1200 kg / cm ^2.
It was injection-molded into the mold under the conditions of. The obtained molded body is 300
The wax binder was removed by keeping the temperature at ℃. After that, it was sintered at a temperature of 1400 ° C. for 2 hours and cooled at the cooling rate shown in Table 1 to room temperature.

[0016]

[Table 1]

An exciting coil and a search coil were wound together for 50 turns on the sintered body thus obtained, a BH hysteresis curve was drawn by a DC recording flux meter, and an external magnetic field was drawn.
The magnetic flux density (B ₃₅ ), coercive force (Hc), and maximum magnetic permeability (μm) were determined at ₃₅ Oe. The results are shown in Table 2.

[0018]

[Table 2]

Comparative Examples 1 to 10 are examples produced by the same method as that of the example, but the composition, the particle size of the raw material powder, the cooling rate, etc. were changed. In Comparative Example 1, since the P content is less than 0.1% by weight, the sintered density is low and the magnetic flux density (B ₃₅ ) is inferior. In Comparative Example 2, since the P content exceeds 1% by weight, the maximum magnetic permeability (μm) decreases, and the coercive force (H
c) is also high. In Comparative Example 3, the V content was 0.
Since it is less than 3% by weight, the electric resistance is poor. In Comparative Example 4, since the V content exceeds 3% by weight, the maximum magnetic permeability (μm) is decreased and the coercive force is also increased.

In Comparative Example 5, the magnetic flux density (B ₃₅ ) is inferior because the Co content exceeds 60% by weight. In Comparative Example 6, since the Co content is less than 40% by weight, the magnetic flux density (B ₃₅ ) is inferior. In Comparative Example 7, Comparative Example 8 and Comparative Example 9, the cooling after sintering was performed by hot water cooling, water cooling with 25 ° C. water, water cooling with 0 ° C. water, and a cooling rate of 50 ° C. /
Since it exceeds min, the magnetic properties are greatly inferior in all cases. In Comparative Example 10, Fe-50 wt% Co
Since the average particle size of the alloy powder is coarser than 45 μm, the sintered density is low and the magnetic properties are poor.

The sintered density of the sintered body is 93% or more, the electric resistance is 30 μΩ or more, and the magnetic flux density (B ₃₅ ) is 190.
It is desirable that the coercive force (Hc) is 00 G or more, the coercive force (Hc) is 3 Oe or less, and the maximum magnetic permeability (μm) is 3000 G / Oe or more. As is clear from the above results, the sintered body produced by the method of the present invention has low coercive force, high magnetic permeability, and high electric resistance in soft magnetic characteristics.

[0022]

INDUSTRIAL APPLICABILITY The present invention has excellent soft magnetic properties, has a higher density than conventional Fe-Co alloys and Fe-Co-V alloys, and has improved electrical resistance. As a result, a remarkable effect that is industrially advantageous, such as a stable supply of a soft magnetic sintered body having a complicated shape and high performance soft magnetic characteristics, is recognized.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C22C 38/00 303 S 304 38/12

Claims (3)

[Claims] 1. Co of 40 to 60% by weight and V of 0.3 to
3% by weight, P is 0.1 to 1% by weight, and the balance is substantially Fe.
A composition comprising powder and a binder compounded as described above is injection-molded, the obtained molded body is subjected to binder removal treatment, and further subjected to sintering treatment, and then gradually cooling the sintered body. A method for producing a Fe-Co-VP alloy soft magnetic material sintered body, comprising: 2. The cooling rate at the time of gradually cooling the molded body is 2 to 50 ° C.
Fe / min according to claim 1, characterized in that
A manufacturing method of a Co-VP alloy soft magnetic material sintered body. 3. The Fe according to claim 1, wherein the average particle size of the powder is 45 μm or less.
-Method for producing a Co-VP alloy soft magnetic material sintered body.