JP2003293007A - HYDRIDE-COATED Fe-Cr ELECTRICAL STAINLESS STEEL POWDER AND MANUFACTURING METHOD - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide hydride-coated Fe-Cr electrical stainless steel powder and its manufacturing method. <P>SOLUTION: In the hydride-coated Fe-Cr electrical stainless steel powder, the surface of Fe-Cr electrical stainless steel powder is coated with hydride of rare-earth elements including Y, Zr hydride, Ti hydride, Hf hydride, V hydride, Ta hydride or Pd hydride (hereinafter referred to as metal hydride). In the method for manufacturing the hydride-coated Fe-Cr electrical stainless steel powder, the surface of the Fe-Cr electrical stainless steel powder is coated with the metal hydride by a high-speed impact method or a binder method by using the Fe-Cr electrical stainless steel powder having 10 to 150 μm average particle size and powder of the metal hydride having 1 to 10 μm average particle size. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

This invention relates to a hydride-coated Fe-
The present invention relates to a Cr-based electromagnetic stainless steel powder and a method for producing the same.

[0002]

2. Description of the Related Art Generally, it is known that a soft magnetic sintered material obtained by sintering Fe--Cr type electromagnetic stainless steel powder is used for an electromagnetic valve, an iron core of an automobile fuel injection device, a yoke and the like. . The soft magnetic sintered material obtained by sintering the Fe-Cr-based electromagnetic stainless steel powder has excellent corrosion resistance, but has a low specific resistance, and when this is used as a magnetic core, eddy current loss occurs and effective magnetic permeability is generated. It cannot be used for high frequencies because of the decrease in In order to avoid this, metal oxides such as silica, titanium oxide, alumina, boron oxide, iron oxide, and ferrite having a spinel structure, nitrides, fluorides, and chlorides on the surface of Fe-Cr electromagnetic stainless steel powder. , A high-resistance layer-coated soft magnetic powder coated with a substance having a large specific resistance, such as bromide and iodide, was sintered and Fe-C was formed by sintering the high-resistance layer-coated soft magnetic powder.
Silica, titanium oxide, alumina, boron oxide, iron oxide, metal oxide such as ferrite having spinel structure, nitride, fluoride, chloride, bromide, which has a large specific resistance in the grain boundary of r-type electromagnetic stainless steel powder, A composite soft magnetic sintered material having a structure in which iodide or the like is intercalated is already known. In this composite soft magnetic sintered material, a substance having a large specific resistance is interposed between Fe—Cr type electromagnetic stainless steel powder. Therefore, the resistance value becomes large, and the occurrence of eddy current loss is greatly reduced, so that it can be used for high frequencies.

A composite soft magnetic sintered material having a structure in which a substance having a large specific resistance is present between the Fe--Cr type electromagnetic stainless steel powder is a Fe--Cr type electromagnetic stainless steel powder containing silica, titanium oxide, A colloid consisting of metal oxides such as alumina, boron oxide, iron oxide, ferrite, etc., nitrides, fluorides, chlorides, bromides, and iodides is mixed to produce a soft magnetic powder coated with a high resistance layer. It is made by sintering a layer-coated soft magnetic powder. Among the composite soft magnetic sintered materials obtained by sintering these high resistance layer-coated soft magnetic powders, the high-resistance layer obtained by coating the surface of Fe—Cr type electromagnetic stainless steel powder with a ferrite layer having a spinel structure is used. F obtained by sintering the soft magnetic powder coated with the resistance layer
A composite soft magnetic sintered material having a structure in which e-Cr-based electromagnetic stainless steel powders are separated by a ferrite layer has particularly excellent high-frequency characteristics, and thus has attracted the most attention.

[0004]

However, the conventional high resistance layer-coated soft magnetic powder obtained by coating the surface of the Fe--Cr type electromagnetic stainless steel powder with the ferrite layer having the spinel structure is sintered at a high temperature to increase the density. If it is attempted to raise it, the ferrite layer will be decomposed or destroyed so that a sufficient resistance value cannot be obtained, and the actual sintering must be carried out at less than 900 ° C. If it is sintered at such a low temperature, the Fe-Cr type electromagnetic stainless steel will be produced. Although the ferrite layer formed on the surface of the steel powder is extremely less decomposed or destroyed, the density of the obtained composite soft magnetic sinter is decreased due to the low sintering temperature, and therefore the mechanical strength, especially There was a drawback that the folding force was reduced. On the other hand, silica, titanium oxide, alumina, boron oxide, nitride, fluoride, chloride, bromide,
A layer made of a highly resistant material such as iodide having excellent heat resistance is F
Fe formed between grains of e-Cr electromagnetic stainless steel powder
The composite soft magnetic sinter having a structure in which -Cr-based electromagnetic stainless steel powders are isolated from each other is silica, titanium oxide, alumina, boron oxide, nitride, fluoride, chloride, bromide,
Since a high resistance substance such as iodide is stable against heat, even if it is sintered at a high temperature, the high resistance substance powder will not be decomposed or destroyed at the time of sintering. High resistance material powders such as silica, titanium oxide, alumina, boron oxide, nitride, fluoride, chloride, bromide, iodide, etc. are less likely to diffuse and form a solid solution during sintering. Fe-
There is a drawback that a composite soft magnetic sintered material having sufficient mechanical strength cannot be obtained because it interferes with the joining of Cr-based electromagnetic stainless steel powders. However, in recent years, these composite soft magnetic sinter materials are about to be used for parts such as solenoid valves and plungers that are subject to vibration or impact, and the conventional composite soft magnetic sinter material is insufficient in mechanical strength. Therefore, there is a demand for a composite soft magnetic sinter that has high strength and is excellent in magnetic properties and that can be used for parts subject to such vibration or impact.

[0005]

Therefore, the present inventors have
Research was conducted to obtain a composite soft magnetic sintered material having high strength, high density, and high resistance. As a result, (a) Y-on the surface of the Fe-Cr-based electromagnetic stainless steel powder,
Hydrides of rare earth elements (hereinafter represented by R) containing Zr
Hydride, Ti hydride, Hf hydride, V hydride, Ta hydride or Pd hydride (hereinafter,
These are referred to as metal hydrides), and hydride-coated Fe-Cr electromagnetic stainless steel powders are compacted and sintered in a non-oxidizing atmosphere at a temperature of 900 to 1300 ° C, and then in a hydrogen atmosphere. The composite soft magnetic sintered material obtained by the hydrogenation treatment by heating at a temperature of 150 to 800 ° C. has a structure in which the metal hydride is present in the grain boundaries of the Fe—Cr electromagnetic stainless steel powder. The resulting composite soft magnetic sintered material has a high specific resistance, and thus the composite soft magnetic sintered material having a high resistance is obtained. The composite soft magnetic sintered material is sintered at a high temperature. Therefore, it has higher density and higher strength compared with the composite soft magnetic sintered material having iron oxide or ferrite layer, while silica, titanium oxide, alumina, boron oxide, nitride, fluoride, chloride. , A mechanical strength is improved as compared with a conventional composite soft magnetic sinter material in which a layer made of a high resistance material having excellent heat resistance such as bromide and iodide is formed at a grain boundary of Fe—Cr electromagnetic stainless steel powder. B) After finishing the sintering
In the heat treatment step of heat treatment in a hydrogen atmosphere, the degree of hydrogenation of the metal hydride can be adjusted by adjusting the amount of hydrogen contained in the hydrogen atmosphere, whereby the particles of the Fe-Cr-based electromagnetic stainless steel powder can be adjusted. Since the amount of hydrogenation in the metal hydride intervening in the boundary can be adjusted, and the resistance value of the composite soft magnetic sintered material can be adjusted accordingly, a composite that can be used in a wide frequency band from low frequency to high frequency can be adjusted. Research results were obtained, such as obtaining a soft magnetic sintered material.

The present invention has been made on the basis of the results of such research. (1) A hydride-coated Fe-Cr electromagnetic system in which the surface of an Fe-Cr electromagnetic stainless steel powder is coated with a metal hydride. It is characterized by stainless steel powder.

The Fe--Cr electromagnetic stainless steel powder has an average particle size of 10 to 100 μm, and the surface of the Fe--Cr electromagnetic stainless steel powder is preferably coated with a metal hydride. The Fe-Cr electromagnetic stainless steel powder having an average particle size of 10 to 100 µm is a commonly used Fe-Cr electromagnetic stainless steel powder,
It is not particularly new. Therefore, the present invention
(2) A hydride-coated Fe-Cr electromagnetic stainless steel powder in which the surface of an Fe-Cr electromagnetic stainless steel powder having an average particle diameter of 10 to 100 µm is coated with a metal hydride.

The hydride-coated Fe-Cr type electromagnetic stainless steel powder of the present invention mechanically mixes and stirs Fe-Cr type electromagnetic stainless steel powder and metal hydride to obtain Fe-Cr type electromagnetic stainless steel powder and metallic hydrogen. Fe by a mechanochemical reaction by applying mechanical energy between the oxide powders
It can be produced by a method of coating the surface of a —Cr-based electromagnetic stainless steel powder with a metal hydride (hereinafter, this method is referred to as a high-speed impact method).

By this high-speed impact method, hydride-coated Fe-
The metal hydride used in the method for producing the Cr-based electromagnetic stainless steel powder may be a powder, but is not particularly limited to the powder and may be a lump. The reason is that metal hydrides are easier to grind than Fe-Cr electromagnetic stainless steel powders. Therefore, when metal hydrides are added to Fe-Cr electromagnetic stainless steel powders and subjected to the high-speed impact method, the metal hydrides are Since the average particle size of the hard Fe-Cr-based electromagnetic stainless steel powder is hardly changed, the metal hydride is mixed with the Fe-Cr-based electromagnetic stainless steel during the high-speed impact method. This is because the powder is pulverized earlier than the stainless steel powder into a finer powder, and the surface of the Fe—Cr-based electromagnetic stainless steel powder is coated with the metal hydride. However, the metal hydride is Fe-
The finer the Cr-based electromagnetic stainless steel powder, the faster the production of the hydride-coated Fe-Cr-based electromagnetic stainless steel powder by the high-speed impact method. Therefore, the Fe-Cr-based electromagnetic stainless steel powder used for manufacturing the hydride-coated Fe-Cr-based electromagnetic stainless steel powder by this high-speed impact method uses the Fe-Cr-based electromagnetic stainless steel powder having an average particle size of 10 to 100 μm. On the other hand, the metal hydride powder is Fe-C
It is more preferable to use a metal hydride powder having an average particle size that is relatively finer than that of the r-type electromagnetic stainless steel powder: 1 to 10 μm. Therefore, the present invention
(3) Fe-C is obtained by subjecting a mixture of Fe-Cr electromagnetic stainless steel powder and metal hydride to a high-speed impact method.
The hydride-coated Fe- according to (1) or (2) above, wherein the surface of the r-type electromagnetic stainless steel powder is coated with a metal hydride.
It is characterized by a method for producing a Cr-based electromagnetic stainless steel powder.

Further, a binder and a metal hydride powder are added to the Fe-Cr type electromagnetic stainless steel powder, and the mixture is stirred and dried to coat the surface of the Fe-Cr type electromagnetic stainless steel powder with the metal hydride powder with the binder. Fe-C by a method of solidifying (hereinafter referred to as a binder method)
The surface of the r-type electromagnetic stainless steel powder can be coated with a metal hydride. Therefore, the present invention provides (4) F
The binder and the metal hydride powder are added to the e-Cr electromagnetic stainless steel powder, and the surface of the Fe-Cr electromagnetic stainless steel powder is coated with the metal hydride by the binder method of stirring and then drying and solidifying. (1) or (2)
The method for producing an Fe-Cr-based electromagnetic stainless steel powder described above is characterized.

By this binder method, hydride-coated Fe
In order to produce —Cr-based electromagnetic stainless steel powder, an average particle diameter of 10 to 100 μm is added to Fe—Cr-based electromagnetic stainless steel powder, which is relatively finer than that of Fe—Cr-based electromagnetic stainless steel powder. It is preferred to use 10 μm metal hydride powder. The reason is that in the binder method, when the metal hydride is added in a lump form for kneading with the binder, the metal hydride is less likely to be crushed as in the high-speed impact method. Therefore, when the metal hydride is added in a lump form, the metal hydride is added. Is not sufficiently pulverized, so that the particle size varies, and the surface of the Fe—Cr electromagnetic stainless steel powder is not uniformly coated with the metal hydride. Therefore, the present invention provides (5) average particle size: 10
100 μm Fe-Cr electromagnetic stainless steel powder and metal hydride powder having an average particle size of 1 to 10 μm, which is relatively finer than that of Fe-Cr electromagnetic stainless steel powder, are mixed and stirred with a binder, and F is obtained by the binder method.
(1) or (2), wherein the surface of the e-Cr electromagnetic stainless steel powder is coated with a metal hydride.
And a method for producing a Cr-based electromagnetic stainless steel powder.

To produce a composite soft magnetic sintered material by using the hydride-coated Fe-Cr type electromagnetic stainless steel powder of the present invention, the hydride-coated F described in (1) or (2) above is used.
The e-Cr electromagnetic stainless steel powder is compacted, sintered in a non-oxidizing atmosphere at a temperature of 900 to 1300 ° C., and then heated in a hydrogen atmosphere at a temperature of 150 to 800 ° C. for hydrogenation treatment. It is obtained by doing. In this case, the step of hydrogenating by heating at a temperature of 150 to 800 ° C. in a hydrogen atmosphere can be replaced by setting the atmosphere to be a hydrogen atmosphere in the step of cooling after sintering.

In the present invention, R is Y, Ce,
La, Pr, Nd, Sm, Gd, Ho, Er, Yb, L
It is one or more of u. Further, the Fe-Cr-based electromagnetic stainless steel powder for producing the composite soft magnetic sintered material having high strength, high density and high resistance of the present invention is prepared by any of atomizing method, electrolyzing method and reducing method. Produced Fe
-Cr-based electromagnetic stainless steel powder can be used. A specific composition of the Fe—Cr-based electromagnetic stainless steel powder used in the present invention is, in mass%, Cr: 10.
-20%, C: 0.1-0.5%, balance Fe
And Fe-Cr electromagnetic stainless steel (for example, 17% Cr-1% C-Fe) powder having a composition consisting of unavoidable impurities and Cr: 10 to 20%, Mo: 0.1 to 0.5%, Fe with a composition in which the balance is Fe and inevitable impurities
-Cr-based electromagnetic stainless steel (for example, 17% Cr-1%
Mo-Fe) powder and the like are preferable, but the present invention is not particularly limited to this, and other generally known Fe-C
r-based electromagnetic stainless steel powder can be used.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Example 1 As a raw material powder, Fe having an average particle diameter of 55 μm, a composition of components of Cr: 13% and C: 0.2%, and the balance being Fe and inevitable impurities Atomized powder of Cr-based electromagnetic stainless steel was prepared, and further, Y hydride powder, La hydride powder, Ce hydride powder, Nd hydride powder, Sm hydride powder, and Zr each having an average particle diameter of 3 μm. Hydride powder, Ti hydride powder, Hf hydride powder, V hydride powder, Ta hydride powder or Pd hydride powder was prepared. The Y hydride powder, L
a hydride powder, Ce hydride powder, Nd hydride powder, Sm hydride powder, Zr hydride powder, Ti hydride powder, Hf hydride powder, V hydride powder, Ta hydride powder or Pd hydride powder. Fe-Cr system electromagnetic stainless steel Atomized powder and charged into a high-speed impact device having a rotatable blade, the number of rotations of the blade: 6
000r. p. m. The mixture is agitated by rotating for 3 minutes, and the hydride powder left uncoated is removed by sieving to remove Fe-Cr-based electromagnetic stainless steel powder of the present invention (hereinafter referred to as the present powder). 1-11
Was produced. 6 ton / c of these powders 1 to 11 of the present invention
By applying molding pressure of m ² , length: 40 mm, width: 1
0 mm, thickness: molding a compact having a dimension of 5 mm,
The obtained compact is sintered in an inert gas atmosphere at a temperature of 1100 ° C., and hydrogen is supplied so that the atmosphere becomes a hydrogen atmosphere when cooled to 800 ° C. in the cooling step after sintering. The atmosphere was maintained until it was cooled to at least 150 ° C., and hydrogenation was performed to produce a composite soft magnetic sintered material.

Conventional Example 1 For comparison, Fe-Cr electromagnetic stainless steel atomized
On the surface of the powder (Mn ₁₇Zn₁₆Fe₆₇)₃O_FourCoated
Conventional ferrite-coated Fe-Cr electromagnetic stainless steel powder
Prepare powder (hereinafter referred to as conventional powder) and use this conventional powder
6 ton / cm ²Vertical: 40 by applying molding pressure
Consolidation with dimensions of mm, width: 10 mm, thickness: 5 mm
Form the body and sinter the resulting compact at 800 ° C
To produce a composite soft magnetic sintered material that has a ferrite phase at the grain boundaries.
It was made.

The relative density and transverse rupture strength of the thus obtained composite soft magnetic sintered material were measured, and the results are shown in Table 1. Furthermore, the magnetic flux density, resistance value and frequency: 1
The relative permeability at a high frequency of 00 KHz was measured, and the results are shown in Table 1.

[0017]

[Table 1]

From the results shown in Table 1, the powders of the present invention 1 to
The composite soft magnetic sintered material prepared in No. 11 is comparable to the composite soft magnetic sintered material prepared by the conventional powder having a ferrite phase in the grain boundary in the magnetic characteristics and the resistance value, It can be seen that the composite soft magnetic sintered material produced in No. 11 has a higher density and higher mechanical strength than the composite soft magnetic sintered material produced by the conventional powder.

Example 2 The average particle size prepared in Example 1 was 55 μm, the composition of the components was Cr: 13%, C: 0.2%, and the balance was Fe.
Atomized powder of Fe-Cr electromagnetic stainless steel composed of unavoidable impurities and fine average particle size: 3
Y hydride powder with μm, La hydride powder, Ce
Hydride powder, Nd hydride powder, Sm hydride powder,
2% each of Zr hydride powder, Ti hydride powder, Hf hydride powder, V hydride powder, Ta hydride powder or Pd hydride powder, and polyvinyl alcohol: 0.05% as a binder, balance: Fe -C
r-type electromagnetic stainless steel atomized powder was compounded, and this compounded powder was charged into a processing device having a rotatable stirring blade, and the stirring blade was rotated at a rotation speed of 1000 r. p. m. In 2
By rotating for 0 minutes to mix and stir, the hydride-coated Fe-Cr-based electromagnetic stainless steel powders of the present invention (hereinafter referred to as the present invention powders) 12 to 22 are produced, and these powders are mixed at 6 to
Vertical: 40 mm by applying molding pressure of n / cm ² .
A compacted body having dimensions of width: 10 mm and thickness: 5 mm is molded, and the obtained compacted body is subjected to 1150 in an inert gas atmosphere.
Sintered at a temperature of ℃, 800 ℃ in the cooling process after sintering
Hydrogen was supplied so that the atmosphere became a hydrogen atmosphere at the time of cooling, and this hydrogen atmosphere was held at least at 150 ° C. until it was hydrogenated to prepare a composite soft magnetic sintered material.

The relative density and the transverse rupture strength of the thus obtained composite soft magnetic sintered material were measured, and the results are shown in Table 1. Further, the magnetic flux density, the resistance value and the frequency: 1
The relative magnetic permeability was measured at a high frequency of 00 KHz, and the results are shown in Table 2.

[0021]

[Table 2]

The composite soft magnetic sintered materials prepared from the powders 12 to 22 of the present invention shown in Table 2 are compared with the composite soft magnetic sintered materials prepared from the conventional powder shown in Table 1 having a ferrite phase at the grain boundary. In addition, the magnetic properties and resistance values are comparable to each other, and the composite soft magnetic sintered material produced by the powders 12 to 22 of the present invention has a higher density than the composite soft magnetic sintered material produced by the conventional powders. In addition, it can be seen that the mechanical strength is higher.

[0023]

INDUSTRIAL APPLICABILITY The present invention can provide a composite soft magnetic sintered material having a high density, excellent mechanical strength, and high relative permeability at high frequencies, and brings excellent effects in the electric and electronic industries. Is.

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Claims (5)

[Claims] 1. A hydride of a rare earth element containing Y, a hydride of Zr, on the surface of an Fe—Cr-based electromagnetic stainless steel powder,
Ti hydride, Hf hydride, V hydride, Ta
Or Fe-Cr-based electromagnetic stainless steel powder coated with hydride of Pd or Pd (hereinafter referred to as metal hydride). 2. Fe-Cr having an average particle size of 10 to 100 μm.
A hydride-coated Fe-Cr system electromagnetic stainless steel powder characterized in that the surface of the system-based electromagnetic stainless steel powder is coated with a metal hydride. 3. Fe-Cr having an average particle size of 10 to 100 μm.
-Based electromagnetic stainless steel powder and metal hydride are mixed and stirred, and mechanical energy is applied to the Fe-Cr powder.
The method for producing a hydride-coated Fe-Cr electromagnetic stainless steel powder according to claim 1 or 2, wherein the surface of the electromagnetic stainless steel powder is coated with a metal hydride. 4. A method for coating a surface of an Fe—Cr electromagnetic stainless steel powder with a metal hydride by adding a metal hydride powder and a binder to an Fe—Cr electromagnetic stainless steel powder, stirring and drying and solidifying. The method for producing a hydride-coated Fe-Cr-based electromagnetic stainless steel powder according to claim 1 or 2. 5. The Fe-Cr type electromagnetic stainless steel powder has an average particle size of 10 to 100 μm, the metal hydride powder has an average particle size of 1 to 10 μm, and the average particle of the metal hydride powder. The method for producing a hydride-coated Fe-Cr-based electromagnetic stainless steel powder according to claim 4, wherein the diameter is relatively finer than the average particle diameter of the metal hydride powder.