JP2003293003A - HYDRIDE-COATED Fe POWDER AND MANUFACTURING METHOD - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide hydride-coated Fe powder and its manufacturing method. <P>SOLUTION: In the hydride-coated Fe powder, the surface of Fe 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 powder, the surface of the Fe powder is coated with the metal hydride by a high-speed impact method or a binder method by using the Fe 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]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydride-coated Fe powder and a method for producing the same.

[0002]

2. Description of the Related Art Generally, a soft magnetic sintered material obtained by sintering Fe powder is used for not only DC relays, speakers, electromagnets, electromagnetic clutches, but also low-loss yokes for motors or actuators, magnetic cores for transformers, choke coils, etc. It is known to be used for. However, this soft magnetic sintered material has a low specific resistance, and when it is used as a magnetic core, eddy current loss occurs and the effective magnetic permeability is reduced, so that it cannot be used for high frequencies. In order to avoid this, silica, titanium oxide, alumina,
Manufacture of high resistance layer-coated soft magnetic powder coated with substances with large specific resistance such as boron oxide, iron oxide, metal oxide such as ferrite having spinel structure, nitride, fluoride, chloride, bromide, iodide, etc. The high resistance layer-coated soft magnetic powder is sintered to obtain a large specific resistance at the grain boundary of the Fe powder such as silica, titanium oxide, alumina, boron oxide, iron oxide, metal oxide such as ferrite having a spinel structure, and nitriding. A composite soft magnetic sintered material having a structure in which a substance, a fluoride, a chloride, a bromide, an iodide and the like are interposed is already known, and this composite soft magnetic sintered material has a large specific resistance between Fe powders. Since the substance is interposed, the resistance value becomes large, and the occurrence of eddy current loss is greatly reduced, so that it can be used for high frequency.

A composite soft magnetic sintered material having a structure in which a substance having a large specific resistance is present between the Fe powder is Fe.
Silica, titanium oxide, alumina, boron oxide, iron oxide, metal oxides such as ferrite, nitride, fluoride, etc.
It is prepared by mixing a colloid consisting of chloride, bromide and iodide to prepare a high resistance layer-coated soft magnetic powder, and sintering the high resistance layer-coated soft magnetic powder. Among the composite soft magnetic sintered materials obtained by sintering these high resistance layer-coated soft magnetic powders, high resistance layer-coated soft magnetic powders obtained by coating the surface of Fe powder with a ferrite layer having a spinel structure The composite soft magnetic sintered material having a structure in which Fe powders obtained by sintering are isolated from each other by a ferrite layer has particularly excellent high frequency characteristics, and thus has attracted the most attention.

[0004]

However, if the conventional high resistance layer-coated soft magnetic powder obtained by coating the surface of Fe powder with a ferrite layer having a spinel structure is sintered at high temperature to increase the density, the ferrite Since the layer is decomposed or destroyed, a sufficient resistance value cannot be obtained, and the actual sintering must be performed at less than 900 ° C. When the sintering is performed at such a low temperature, the layer of ferrite formed on the surface of the Fe powder is formed. On the other hand, although decomposition or destruction is extremely small, there is a drawback that the density of the obtained composite soft magnetic sintered material is lowered because of the low sintering temperature, and therefore the mechanical strength, especially the transverse rupture strength is 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
The composite soft magnetic sinter having a structure formed between the grains of the e powder and separating the Fe powders 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 is not decomposed or destroyed at the time of sintering, but Fe powder and silica,
Titanium oxide, alumina, boron oxide, nitride, fluoride, chloride, bromide, iodide and other high-resistance substance powder is less likely to diffuse and solid solution during sintering, therefore,
These high-resistance substance powders have a drawback in that a composite soft magnetic sintered material having sufficient mechanical strength cannot be obtained because they interfere with the joining of Fe 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) a rare earth element containing Y (hereinafter,
R), Zr hydride, Ti hydride, Hf hydride, V hydride, Ta hydride or Pd hydride (hereinafter referred to as metal hydride). The Fe powder coated with hydride is compacted, sintered in a non-oxidizing atmosphere at a temperature of 900 to 1300 ° C., and then heated at a temperature of 150 to 800 ° C. in a hydrogen atmosphere to be hydrogenated. The composite soft magnetic sintered material thus obtained is a composite soft magnetic sintered material having a structure in which the metal hydride is present in the grain boundary of Fe powder,
Since this metal hydride coating has a high specific resistance value,
A composite soft magnetic sintered material having high resistance is obtained, and since this composite soft magnetic sintered material is sintered at high temperature, the composite soft magnetic sintered material has high density and high density as compared with the composite soft magnetic sintered material having an iron oxide or ferrite layer. It has high strength, while silica, titanium oxide,
Compared with the conventional composite soft magnetic sinter that has a layer made of a highly resistant material such as alumina, boron oxide, nitride, fluoride, chloride, bromide, and iodide at the grain boundary of Fe powder (B) In the heat treatment step of performing heat treatment in a hydrogen atmosphere after the completion of the sintering, the degree of hydrogenation of the metal hydride can be adjusted by adjusting the amount of hydrogen contained in the hydrogen atmosphere. As a result, the amount of hydrogenation in the metal hydride present at the grain boundaries of the Fe powder can be adjusted, and thereby the resistance value of the composite soft magnetic sintered material can be adjusted, so that it can cover a wide range from low frequencies to high frequencies. Research results have been obtained, such as obtaining a composite soft magnetic sintered material that can be used in various frequency bands.

The present invention has been made based on the results of such research, and is characterized by (1) a hydride-coated Fe powder in which the surface of the Fe powder is coated with a metal hydride.

The Fe powder has an average particle size of 10 to 100 μm.
m, and the surface of this Fe powder is preferably coated with a metal hydride. Average particle size: 10 to 100 μm
The Fe powder containing is a commonly used Fe powder and is not particularly novel. Therefore, the present invention is characterized by (2) a hydride-coated Fe powder in which the surface of an Fe powder having an average particle diameter of 10 to 100 μm is coated with a metal hydride.

The hydride-coated Fe powder of the present invention is Fe
A method in which the powder and the metal hydride are mechanically mixed and stirred, and mechanical energy is applied between the Fe powder and the metal hydride powder to coat the surface of the Fe powder with the metal hydride by a mechanochemical reaction (hereinafter, This method is referred to as a high speed impact method).

The metal hydride used in the method for producing the hydride-coated Fe powder by the high-speed impact method 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 powders, so when metal hydrides are added to Fe powders and subjected to a high-speed impact method, the metal hydrides are ground earlier into finer powders, while Since the average particle size of the hard Fe powder hardly changes, the metal hydride is crushed into finer powder before the Fe powder during the implementation of the high-speed impact method, and the surface of the Fe powder is covered with the metal hydride. This is because it will be covered with. However, if the metal hydride is finer than the Fe powder, the production of the hydride-coated Fe powder by the high-speed impact method becomes faster. Therefore, the Fe powder used for manufacturing the hydride-coated Fe powder by this high-speed impact method uses the Fe powder having an average particle size of 10 to 100 μm, while the metal hydride powder has a relatively finer average than the Fe powder. More preferably, a metal hydride powder having a particle size of 1 to 10 μm is used. Therefore,
(3) The hydride-coated Fe powder according to (1) or (2) above, wherein the surface of the Fe powder is coated with the metal hydride by subjecting the mixture of the (3) Fe powder and the metal hydride to a high-speed impact method. It is characterized by a manufacturing method.

Further, a binder and a metal hydride powder are added to the Fe powder, and the mixture is stirred and dried to coat the metal hydride powder on the surface of the Fe powder with the binder to solidify the Fe (hereinafter referred to as the binder method). The surface of the powder can be coated with a metal hydride. Therefore, the present invention provides (4) a method of adding a binder and a metal hydride powder to Fe powder, coating the surface of the Fe powder with metal hydride by a binder method in which the binder is stirred and then dried and solidified. Described hydride coating F
The method is characterized by a method for producing e powder.

By this binder method, hydride-coated Fe
To produce a powder, F with an average particle size of 10 to 100 μm is used.
e powder has a relatively finer average particle size than Fe powder: 1 to 1
Preference is given to using 0 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 the particle size varies,
This is because the surface of the powder is not uniformly covered with the metal hydride. Therefore, the present invention provides (5) average particle size: 10
Fe powder of ˜100 μm and metal hydride powder having a finer average particle diameter: 1 to 10 μm than Fe powder are mixed and stirred with a binder, and the surface of the Fe powder is coated with the metal hydride by the binder method ( The method is characterized by the method for producing a hydride-coated Fe powder according to 1) or (2).

In order to manufacture a composite soft magnetic sintered material using the hydride-coated Fe powder of the present invention, the hydride-coated Fe powder as described in (1) or (2) above is pressed and non-oxidized. It is obtained by performing a hydrogenation treatment by sintering in a hydrogen atmosphere at a temperature of 150 to 800 ° C. after sintering in an oxygen atmosphere at a temperature of 900 to 1300 ° C. 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, as the Fe powder for producing the composite soft magnetic sintered material having high strength, high density and high resistance of the present invention, the Fe powder produced by any of the atomizing method, the electrolytic method and the reducing method is used. can do. The Fe powder used in the present invention is F having soft magnetism.
Any Fe powder may be used as long as it is an e powder.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Example 1 As a raw material powder, an Fe atomized powder having an average particle size of 70 μm was prepared, and further, a hydride powder of Y and an hydride powder of La each having an average particle size of 3 μm, 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. A hydride powder was prepared. Y hydride powder, La hydride powder, Ce hydride powder, N
d hydride powder, Sm hydride powder, Zr hydride powder, Ti hydride powder, Hf hydride powder, V
Hydride powder of Ta, hydride powder of Ta or hydride powder of Pd was charged together with Fe atomized powder into a high-speed impact device having a rotatable blade, and the number of rotations of the blade was 6000 rpm. p. m. The mixture was agitated by rotating it for 3 minutes, and the remaining hydride powder not covered was removed by sieving to produce Fe powders 1 to 11 of the present invention (hereinafter referred to as the present powder). . By applying a molding pressure of 6 ton / cm ² to the powders 1 to 11 of the present invention, length: 40 mm, width: 10 mm, thickness: 5
A compact having a size of mm is molded, the obtained compact is sintered in an inert gas atmosphere at a temperature of 1100 ° C., and the atmosphere is hydrogen when cooled to 800 ° C. in the cooling step after sintering. Was supplied so that the hydrogen atmosphere was maintained at a temperature of at least 150 ° C. until hydrogenation was performed to prepare a composite soft magnetic sintered material.

Conventional Example 1 For comparison, (Mn ₁₇ Z was formed on the surface of the Fe atomized powder.
n ₁₆ Fe ₆₇ ) ₃ O ₄ coated conventional ferrite coated Fe
A powder (hereinafter referred to as a conventional powder) is prepared, and a vertical pressure of 4 is obtained by applying a molding pressure of 6 ton / cm ² to the conventional powder.
A compacted body having a size of 0 mm, width: 10 mm, and thickness: 5 mm was molded, and the obtained compacted body was sintered at 800 ° C. to prepare a composite soft magnetic sintered material having a ferrite phase at grain boundaries.

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 Fe atomized powder having an average particle size of 70 μm prepared in Example 1 was added to each of Y hydride powder, La hydride powder, and Ce hydrogen having a fine average particle size of 3 μm. 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. 2% each, and polyvinyl alcohol as a binder: 0.05
%, The balance: Fe atomized powder was blended, and this blended 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. The hydride coating F of the present invention is mixed and stirred by rotating at 20 ° C. for 20 minutes.
e powders (hereinafter referred to as powders of the present invention) 12 to 22 are produced, and a compaction body having dimensions of length: 40 mm, width: 10 mm, thickness: 5 mm is produced by applying a molding pressure of 6 ton / cm ² to these powders. The compacted body obtained by molding is sintered in an inert gas atmosphere at a temperature of 1150 ° C., and hydrogen is supplied so that the atmosphere becomes a hydrogen atmosphere when cooled to 800 ° C. in the cooling step after sintering. By holding this hydrogen atmosphere until it was cooled to at least 150 ° C., hydrogenation treatment was performed to produce 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.

Claims (5)

[Claims] 1. A hydride of a rare earth element containing Y, a hydride of Zr, a hydride of Ti, a hydride of Hf, a hydride of V, a hydride of Ta, a hydride of Ta or a hydride of Ta (Pd) on the surface of Fe powder. Hereinafter, these are referred to as metal hydrides) are coated with hydride-coated Fe powder. 2. A hydride-coated Fe powder, characterized in that the surface of the Fe powder having an average particle diameter of 10 to 100 μm is coated with a metal hydride. 3. An Fe powder having an average particle size of 10 to 100 μm and a metal hydride are mixed and stirred to apply mechanical energy to coat the surface of the Fe powder with the metal hydride. 1. The method for producing the hydride-coated Fe powder according to 1 or 2. 4. Fe powder prepared by adding a metal hydride powder and a binder to Fe powder, stirring and drying and solidifying Fe.
The method for producing a hydride-coated Fe powder according to claim 1, wherein the surface of the powder is coated with a metal hydride. 5. The Fe powder has an average particle diameter of 10 to 100 μm.
m, the metal hydride powder has an average particle size of 1 to 10
5. The method for producing a hydride-coated Fe powder according to claim 4, wherein the metal hydride powder has an average particle size of μm and the average particle size of the metal hydride powder is relatively finer than the average particle size of the metal hydride powder.