JPH06151136A - Powder of metal-based permanent magnet material - Google Patents

Abstract

PURPOSE:To provide powder of metal-based permanent magnet with excellent cost performance having a high magnetic characteristics. CONSTITUTION:Crystal structure has a hexagonal, tetragonal or prismatic system, the main components are one or more kinds of Fe, Co, Ni and Mn, elements of one or more kinds selected from B, C, N, P, Si, Al, Ti, Ge, Ga V, Mo, Pt, Pd, Sn, Zr, Nb, As, Ta, Hf, Bi and Cr are contained, and their mean particle size is 0.001 to 10mum for the powder of metallic-based permanent magnet material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal-based permanent magnet powder having excellent magnetic properties and cost performance.

[0002]

2. Description of the Related Art In recent years, with the development of electronic devices and electronic parts, various permanent magnet materials have been used. Examples of these permanent magnet materials include:
Broadly classified, there are a bulk magnet represented by a powder metallurgy method or a casting method, and a bonded magnet obtained by molding a permanent magnet powder with a binder. The number of such bonded magnets is increasing owing to their advantages such as freedom of shape, good dimensional accuracy, and light weight.

As the permanent magnet material powder used for such a bonded magnet, hard ferrite type, alnico type and rare earth-transition metal type are used. For example, rare earth-transition metal type is Sm-Co type. -5 type, 2-17
Type, Nd-Fe-B system, and more recently, Sm-Fe-N system, which has been recently discovered and is currently being researched, are being put to practical use or being developed. When high magnetic properties are required among these, rare earth-transition metal magnet powder is used.

[0004]

However, in the conventional permanent magnet powder, hard ferrite is inexpensive but has low magnetic properties, and alnico is relatively inexpensive, but coercive force is low among magnetic properties. The rare earth-transition metal system has a problem that it is quite expensive although it has high magnetic properties. In addition, all the conventional magnetic powders for bonded magnets are manufactured by a metallurgical method, and only iHc at a level considerably lower than theoretically held iHc is realized. This is because the metallurgical method requires heat treatment at a considerably high temperature in order to make the alloy or oxide into a desired crystal system, so that structural defects and strain remain inside. Conceivable. Moreover, in order to make powder, it is necessary to crush the produced alloy lump or ribbon into magnetic powder of 1 mm or less, but in this case, most of them are magnetic powder by the mechanical pulverization method at present. Due to structural defects and strains remaining inside the magnetic powder even by such mechanical pulverization, only iHc of the magnetic powder is significantly lower than the theoretical value.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the prior art as described above and to provide metal-based permanent magnet powder having high magnetic properties and excellent cost performance. To do. Specifically, the present invention solves the above-mentioned problems of the prior art by the method described below. (1) The crystal structure is a hexagonal crystal, a tetragonal crystal, or an orthorhombic crystal, at least one of Fe, Co, Ni, and Mn is a main component, and B, C, N, P, Si, Al, and T
i, Ge, Ga, V, Mo, Pt, Pd, Sn, Zr,
An average particle diameter of 0.0 containing one or more elements selected from Nb, As, Ta, Hf, Bi and Cr
Metal-based permanent magnet material powder having a particle size of 01 to 10 μm. (2) crystal _{type, AuCu-I, AuCu 3 -I} , Mn
Bi, W ₂ C, CuPt, Ni ₂ Cr, Cr ₂ Al, C
uAu-II, WC, Fe ₂ P, ZnS, PbO, TiO
₂ , FeS ₂ , β-U, Ag ₃ Mg, Ni ₃ V, Ni ₂
The metal-based permanent magnet material powder according to (1), which is one kind or a combination of a plurality of In and Fe ₃ C.

[0006]

With the structure of the present invention, it has both of the advantages that it has high magnetic properties and that it is possible to use an inexpensive raw material mainly composed of an iron alloy.
It is possible to provide metal-based permanent magnet powder having high cost performance.

[0007]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto. In the present invention, it is essential that the crystal structure of the metal-based magnet powder be hexagonal, tetragonal or orthorhombic. This is because in order to have a high coercive force as a permanent magnet material,
This is because the crystal structure needs to have uniaxial magnetic anisotropy, and for that purpose, it is important that the crystal structure has lower symmetry.

The alloy composition of the present invention is Fe, Co, Ni, M.
Although at least one of n is the main component, it is preferable that Fe is the main component and Fe is partially replaced with Co or Ni. The content of these transition metals is preferably 50 atomic% or more. When it is 50 atomic% or less, the saturation magnetization is significantly lowered. Further, when a part of Fe is replaced with Co or Ni, the substitution amount is preferably within 50 atomic% of Fe.

Although it is possible to realize a metal-based permanent magnet powder by using at least one of Fe, Co, Ni, and Mn as a main component, in order to achieve better magnetic characteristics, the present invention is used. Then, the additive is added. The additive in the present invention is B (boron), C (carbon), N (nitrogen), P (phosphorus), Si (silicon), Al (aluminum), Ti.
(Titanium), Ge (Germanium), Ga (Gallium), V (Vanadium), Mo (Molybdenum), Pt
(Platinum), Pd (palladium), Sn (tin), Zr
(Zirconium), Nb (niobium), As (arsenic), T
One or more elements selected from a (tantalum), Hf (hafnium), Bi (bismuth) or Cr (chromium) are selected, but the addition amount is 50 atomic% or less, particularly 35 atomic% or less. It is preferable. If the content of the additional element exceeds the above range, the saturation magnetization is significantly reduced, which is not preferable. Furthermore, the present invention also includes a composition containing oxygen which is an industrially unavoidable impurity.

The average particle size of the metal magnet powder of the present invention is
It is in the range of 0.001 to 10 μm, but preferably 0.
005 to 1 μm, more preferably 0.01 to
It is 0.5 μm. If the average particle size is less than 0.001 μm, superparamagnetic behavior becomes severe and the coercive force is extremely reduced. On the other hand, if it is larger than 10 μm, it becomes multi-domain particles, which causes a decrease in coercive force.

In order to prevent oxidation and aggregation of the magnet powder produced in the present invention, an organic coating, an inorganic coating, or a metal oxide may be formed on the surface. Further, the surface of the metal particles may be coated with a ceramic coating of Al ₂ O ₃ , SiO ₂ , TiO ₂ or the like in order to prevent the metal particles from aggregating and growing when heat-treated.

The shape of the metal particles in the present invention is spherical,
An elliptical shape, a needle shape, and shapes similar to these can be exemplified. These shapes can be appropriately selected according to the purpose.

Next, one embodiment of the method for producing the above-mentioned metallic permanent magnet powder will be described, but the present invention is not limited thereto. The metal-based permanent magnet powder in the present invention is a method of directly precipitating metal fine particles by dissolving a metal salt in a solution and adding a reducing agent, and a precursor fine particle by dissolving a metal salt in a solution and adding a precipitating agent. After precipitation, it may be produced by a method of reducing the fine particles, a method of producing a bulk magnet by an ordinary powder metallurgical method and crushing it, or a method of producing an ultra-quenched ribbon and crushing this. I can. In order to obtain the fine metal powder having the average particle diameter of the present invention, among the above methods, the method of direct reduction in a solution and the method of precipitating precursor fine particles in a solution and reducing the same are preferable. Next, a more detailed description will be given together with a specific experimental procedure.

(Examples 1 to 4) Chlorides containing respective metal elements were dissolved in ion-exchanged water so that the alloy compositions shown in "Table 1" were obtained, and dissolved in ion-exchanged water as a precipitant. 1.5 equivalents of metal salt was added to NaOH to form a fine particle precursor precipitate. Next, the precursor fine particles were reduced by heat treatment at 400 ° C. for 6 hours in a hydrogen stream (500 ml / min) to obtain alloy fine particles. The magnetic characteristics of the obtained alloy fine particles were measured by VSM. The results are shown in "Table 1". Further, the morphology of the obtained alloy fine particles was observed with an electron microscope, and the average particle diameter was determined from this. Furthermore, the crystal structure of the alloy fine powder was identified by X-ray diffraction. The results are shown in "Table 1".

[0015] (Example 5-6) "Table 1" so that the alloy compositions shown in, the metal containing the respective metal element propoxide _{[Fe (O-n-C 3} H 7) 3, Co (O -N-
_{C 3 H 7) 3, B-} (O-n-C 3 H 7 OH) 3, PO
- a _{(n-C 3 H 7 OH} ) 3 ] was prepared a homogeneous solution by a predetermined amount mixed in n-C ₃ H ₇ OH. Next, while maintaining the adjusted solution at 80 ° C., a solution prepared by mixing distilled water and n-C ₃ H ₇ OH was added, and a precipitate was generated by hydrolysis. After removing the generated precipitate by centrifugation,
It was dried at 100 ° C. to obtain precursor fine particles. Then, alloy fine particles were obtained by heat treatment at 400 ° C. for 6 hours in a hydrogen stream (500 ml / min). The magnetic properties, average particle size, and crystal structure of the obtained alloy fine particles were measured by the same method as in Example 1, and the results are shown in "Table 1".

Example 7 A chloride containing each metal element was dissolved in ion-exchanged water so that the alloy composition shown in Table 1 was obtained, and NaOH dissolved in the ion-exchanged water was used as a precipitant. 1.5 equivalents of the metal salt was added to generate a fine particle precursor precipitate. Next, the precursor fine particles were reduced by heat treatment at 400 ° C. for 6 hours in a hydrogen stream (500 ml / min) to obtain alloy fine particles. The obtained alloy fine particles were heat-treated at 500 ° C. for 5 hours in an ammonia atmosphere to diffuse nitrogen. As a result of analyzing the nitrogen content and the Fe and Co contents of the alloy particles in which nitrogen is diffused,
The composition shown in "Table 1" was obtained. The magnetic properties, average particle size, and crystal structure of the nitrogen-containing alloy fine particles are shown in Example 1.
Measurement was carried out in the same manner as in, and the results are shown in "Table 1".

(Comparative Example 1) A chloride containing each metal element was dissolved in ion-exchanged water so as to have the alloy composition shown in "Table 1", and NaOH dissolved in the ion-exchanged water was used as a precipitating agent. 1.5 equivalents of the metal salt was added to generate a fine particle precursor precipitate. Next, the precursor fine particles were reduced by heat treatment at 400 ° C. for 6 hours in a hydrogen stream (500 ml / min) to obtain alloy fine particles. The magnetic properties, average particle size and crystal structure of the obtained alloy fine particles are shown in Example 1.
It measured by the method similar to. The results are shown in "Table 1".

[0018]

[Table 1]

From the above comparison, it can be seen that the magnet powder of the present invention has better magnetic characteristics than the conventional magnet powder.

[0020]

According to the present invention, it is possible to obtain a metal-based permanent magnet material powder which has high magnetic characteristics and is inexpensive and excellent in cost performance. Therefore, the problem of achieving high magnetic properties while using inexpensive raw materials, which was difficult to achieve with conventional hard ferrite-based, alnico-based, and rare earth-transition metal-based permanent magnet material powders, can be achieved. It is possible to greatly alleviate restrictions in industrial use, and expand the applications of permanent magnet materials.

Claims (2)

[Claims] 1. A crystal structure of hexagonal crystal, tetragonal crystal or orthorhombic crystal, at least one of Fe, Co, Ni and Mn as a main component, and B, C, N, P, Si,
Al, Ti, Ge, Ga, V, Mo, Pt, Pd, S
Metal-based permanent magnet material powder having an average particle size of 0.001 to 10 μm, containing one or more elements selected from n, Zr, Nb, As, Ta, Hf, Bi or Cr. 2. The crystal form is AuCu-I or AuCu _3-.
I, MnBi, W ₂ C, CuPt, Ni ₂ Cr, Cr ₂
Al, CuAu-II, WC, Fe ₂ P, ZnS, Pb
O, TiO ₂ , FeS ₂ , β-U, Ag ₃ Mg, Ni ₃
The metal-based permanent magnet material powder according to claim 1, which is one kind or a combination of plural kinds of V, Ni ₂ In, and Fe ₃ C.