JPS60130103A - Magnetic powder and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a magnetic material of superfine powder by finely pulverizing a magnetic base material which contains Fe group metal Sm, Nd by an evaporating process. CONSTITUTION:When base alloy SmxNd1-xCo (0.1<x<0.8) is filled in an active H-molten metal reaction chamber and a plasma arc current is held at 20-30 amperes in 100%-H2 atmosphere, magnetic particles of superfine powder having approx. 600Angstrom of mean diameter is obtained. When Nd is contained in the base alloy, Sm is effectively contained (e.g., at 1% or higher of atomic ratio) by an active H-molten metal reaction process to obtain the superfine powder having excellent rectangular ratio and coercive force, and the powder is adapted for the power of magnetic recording medium used in horizontal or vertical magnetic recorder/reproducer system.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic powder and a method for producing the same, and in particular, to a magnetic powder used for magnetic recording media such as magnetic tapes and magnetic disks, or for electromagnetic/hard disks. This invention relates to a fine powder magnetic material and its manufacturing method.

[Conventional technology and problems]

Samarium (element symbol Sm) and iron group metals (especially cobal)
It has been pointed out that alloys or intermetallic compounds with Co) have better magnetic properties than those without samarium.

However, it is extremely difficult to produce a powdered magnetic material made of samarium-containing iron group metals, and all attempts at pulverization have ended in failure.

That is, when trying to turn a samarium-containing cobalt base material into ultrafine powder by an evaporation method such as an active hydrogen-molten metal reaction method, due to the high vapor pressure of samarium,
This is thought to be due to samarium being vaporized by plasma generation, atomized, and shaken. For example, when a SmCo4 mother alloy is made into an ultrafine powder by an active hydrogen-molten metal reaction method, the magnetic properties of the ultrafine powder are The material does not contain samarium, and the magnetic properties of the ultrafine powder magnetic material thus obtained are, for example, a saturation magnetization of 54 emu/g1.
The residual magnetization is 11.7 em u / g, and the squareness ratio is 0.
22. It's nothing more than a coercive force of 510 oersted.

[Means for solving problems]

When a base material of a magnetic material containing samarium or an iron group metal is made into an ultrafine powder by an evaporation method such as an active hydrogen-molten metal reaction method, neodymium (
By mixing element symbol Nd), an ultrafine powder magnetic material containing an iron group metal, samarium, and neodymium can be easily obtained. The magnetic properties of metallic ultrafine powder magnetic materials are extremely excellent.

〔Example〕

For example, using an apparatus capable of performing an active hydrogen-molten metal reaction method, that is, using a master alloy composition such as Smx Nd
A magnetic base material such as
When a voltage is applied to the electrodes to be between 0 and 30 amperes,
Ultrafine powder magnetic particles having an average diameter of about 600A are obtained.

When analyzing the magnetic particles obtained in this way, S
When using a master alloy with the composition mo7N'dO, 3CO4, the atomic ratio of Co is 91.9%, Nd is 0.7%, and S
m is 7.4%, and the magnetic properties of this magnetic particle are as follows: saturation magnetization is 516 mu/g, residual magnetization is 21.0 e
It has excellent properties such as mg/g, squareness ratio of 0.41, and coercive force of 760 oerstesoto, and is desirable as a magnetic powder used, for example, in video magnetic tapes.

Also, Sm0. B When using a master alloy with the composition of Ndo2Co4, the magnetic particles obtained by the active hydrogen-molten metal reaction method have an atomic ratio of 89.3% Co and 0.7% Nd.
% and Sm of 10.0%, and the magnetic particles had a saturation magnetization of 63 emu/g.

Residual magnetization is 25.0 emu/g, squareness ratio is 0.40
．． It has an extremely high coercive force of 770 oersted.

In addition, for example, Smx Nd I-x Co can be prepared by an evaporation method such as a plasma method such as an active hydrogen-molten metal reaction method.

Magnetic powder containing cobalt, samarium, and neodymium obtained by ultrafinely powdering the mother alloy of It contains about 0.7 articles.

〔effect〕

The magnetic properties of magnetic powder containing iron group metals, samarium, and neodymium, such as squareness ratio and coercive force, are extremely excellent. It is suitable for materials such as wood.

Even if it contains neodymium, its magnetic properties do not deteriorate, and its magnetic properties are extremely good due to its interaction with samarium.

In addition, when ultra-fine powder is produced, by containing neodymium in the mother alloy, for example, by using an active hydrogen-molten metal reaction method, samarium can be effectively contained, for example, at an atomic ratio of 1% or more, to form a magnetic powder. Excellent characteristics. Ultrafine magnetic particles can be easily obtained.

In addition, the ultrafine powder obtained in the above manner is not acicular but approximately spherical in shape, so it is extremely suitable as a magnetic powder for magnetic recording media used in perpendicular magnetic recording and reproducing systems or horizontal magnetic recording and reproducing systems. 10 desirable.

Patent applicant: Victor Japan Co., Ltd. Katsumi Utaka, a representative

Claims (1)

[Claims] ■ A magnetic powder characterized by containing an iron group metal, samarium, and neodymium. ■ A magnetic powder manufacturing method characterized by pulverizing a magnetic base material containing iron group metals, samarium, and neodymium using an evaporation method.