JPS605041B2 - Method for manufacturing magnetic material for magnetic recording media - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing metal powder.

More specifically, the present invention relates to a method for producing ferromagnetic metal powders, particularly iron or iron-based ferromagnetic metal powders, which are used as high-density magnetic recording media such as magnetic tapes, magnetic drums, and magnetic disks. . Iron or iron-based acicular ferromagnetic metal powders are recognized as very promising as materials for next-generation high-density recording media.

One of the typical production methods of iron or iron-based acicular ferromagnetic metal powder is the heating reduction of iron-based acicular metal oxides or acicular metal acid hydroxides in a reducing gas atmosphere. There is a way to do it. The advantage of this production method is that since the method for producing acicular metal oxides or acicular metal acid hydroxides of desired sizes is known, acicular metal powders of desired sizes can be easily produced. be. A disadvantage of this manufacturing method is that the metal powder tends to crystallize during thermal reduction, which reduces the coercive force of the resulting metal powder. This decrease in coercive force is a characteristic of metal powder as a material for high-density recording media. That is, in the production of metal powder by the thermal reduction method, the most important point is how to prevent race fringes. Conventionally, methods for preventing scale formation of metal powder in the thermal reduction method include methods such as 1) immersing the raw material metal oxide or metal hydroxide in a solution containing Ag+ ions and then reducing the metal powder by heating. , '2' A method is known in which the sample is constantly rotated during thermal reduction to prevent long-term contact between metal powder particles.

Of these, the '11 method involves a process of immersing the raw material in a solution containing Ag+ ions and then drying it, resulting in the problem of increased production costs.
The method requires a sample rotation mechanism that does not leak any reducing gas, which increases the cost of producing metal powder. An object of the present invention is to easily produce metal powder with high coercive force and less caking by a thermal reduction method.

When producing metal powder by a thermal reduction method, the present inventors used a substance with a higher specific heat than the metal in the raw material metal salt powder, metal oxide powder, or metal acid hydroxide powder. By mixing one or more of the powders, granules, plates, or wires, if the powders, granules, plates, or wires are not mixed, It has been discovered that metal powder with high coercive force can be obtained by preventing false condensation due to temperature rise. EXAMPLES Hereinafter, the present invention will be explained in detail with reference to examples.

Example 1 As shown in Figure 1, 75 g of Q-Fe 00-day powder containing 200 quartz wires of 5 lengths approximately uniformly on the diameter 1 side was attached with a 325 mesh stainless steel gold 1 near the center as shown in Fig. 1. A rhombus is inserted into a core tube with an inner diameter of 80 ribs and a length of lm.
It was heated to 270° C. while flowing Kunomin hydrogen gas.

The coercive force of the obtained Fe powder was 123%. In addition,
A magnetic separation method was used to remove the quartz wire from the Fe powder. Example 2 Acicular Q containing 50 mesh refractory brick powder almost uniformly
-Fe00 days
In place of 00-day flour 2, the powder was heated and reduced under the conditions of Example 1.

The coercive force of the obtained Fe powder was 122 e. In addition,
The same method as in Example 1 was used to remove the refractory brick powder from the Fe powder. Comparative Example Q-Fe00 day powder 7 spots were replaced with the quartz wire-containing Q-Fe of Example 1.
It was placed in a bag in place of Day 00 Flour 2, and heated and reduced under the conditions of Example 1.

The holding power of the bound Fe powder was 98%. Example 1
By comparing ~2 with the comparative example, Fe produced by mixing a substance with a larger specific heat than Fe in the raw material Q-Fe00.
It can be seen that the coercive force of the powder is larger than that of Fe powder produced without mixing the above substances in the raw material.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a furnace tube used in carrying out the present invention. multi-figure

Claims (1)

[Claims] 1. When manufacturing metal powder by heating one of metal salt powder, metal oxide powder, and metal acid hydroxide powder in a reducing gas atmosphere, the metal salt powder, metal oxide powder, or A method for producing a magnetic material for a magnetic recording medium, comprising mixing in a metal acid hydroxide powder one or more of powders, granules, plates, or wires made of a substance having a higher specific heat than the metal. .