KR900000272B1 - Making process for magnetic metal powder - Google Patents

Abstract

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Description

Method of manufacturing magnetic magnetic powder for magnetic recording

1 is an electron micrograph (X20,000) of α-FeOOH powder containing Mn.

2 is a graph of oxidation resistance of magnetic powder for magnetic recording.

The present invention relates to a method for producing a magnetic metal powder used as a magnetic recording medium.

Globally, the demand for magnetic recording materials used in recorders, VTRs, various small and large computers is increasing rapidly every year. Until now, the magnetic recording material used in these applications is mainly composed of a coating material made by mixing γ-Fe ₂ O ₃ powder or Co-coated γ-Fe ₂ O ₃ powder with various binders and applying it to a polyester film or another base. have. However, in recent years, recorders, VTRs, computers, and the like have been developed in miniaturization trends, and the magnetic recording materials used therein are also required to have high density and high output. The metal magnetic powder has attracted attention as a high density, high output magnetic recording material because of its excellent magnetic properties, coercive force, residual magnetization, and saturation magnetization, as compared to the oxide magnetic powder mentioned above. However, since the magnetic powder is chemically very unstable, it is easily oxidized and its magnetic properties deteriorate. Accordingly, the present inventors have confirmed through the experiment that the oxidation resistance of the metal magnetic powder can be improved by adding a trace amount of metal or an alloy different from the metal magnetic powder to the metal magnetic powder. The component of the added metal or alloy is one or two components of a small amount of Cu and Zn in Mn and Mn. The amount of Mn is 0.01 atomic% to 2 atomic% with respect to the metallic magnetic powder. For Mn alloys, Mn is 0.01 atomic% to 2 atomic percent with respect to the metallic magnetic powder, and Cu and Zn are 0.01 atomic% to 1 atomic percent, respectively. Added in% range.

Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1

To a 10 L aqueous solution made up of ferrous sulfate containing 9 mole of iron and manganese sulfate containing 0.05 mole of manganese, 9 l of an aqueous solution of 4.6 N of caustic soda was added to make 19 l of aqueous solution. The aqueous solution was heated to 30 ° C. to 40 ° C. and oxidized while blowing air at a flow rate of 200 l / min to precipitate α-FeOOH powder having a needle shape of 0.5 μm long axis and 0.09 μm short axis. Electron micrograph showing the shape of the powder.) The metal containing manganese was reduced by washing this α-FeOOH for 2 hours at a temperature of 700 ℃ or less in an electric furnace of a hydrogen atmosphere having a flow rate of 1 l / min after washing with water. A powder was obtained. The oxidation resistance of the magnetic powder was oxidized in an air atmosphere at 40 ° C including water vapor having a dew point of 40 ° C.

Example 2

19 l of an aqueous solution of 4.6 N of caustic soda was added to a 10 l aqueous solution made of ferrous sulfate containing 9 mole of iron, manganese sulfate containing 0.05 mole of manganese, and copper sulfate containing 0.05 mole of copper. Hereinafter, a metal powder containing manganese and copper was prepared in the same manner as in Example 1, and the results of measuring oxidation resistance are shown in FIG. 2.

Example 3

9 l aqueous solution of 4.6 N of caustic soda was added to a 10 l aqueous solution made of ferrous sulfate containing 9 mole of iron, manganese sulfate containing 0.05 mole of manganese, and zinc sulfate containing 0.005 mole of zinc. Hereinafter, a metal powder containing manganese and zinc was prepared in the same manner as in Example 1, and the results of measuring oxidation resistance are shown in FIG. 2.

[Comparative Example]

19 l of an aqueous solution of 4.6 N of caustic soda was added to 10 l of an aqueous solution of ferrous sulfate containing 9 mole of iron. Hereinafter, a metal powder was prepared in the same manner as in Example 1, and the results of measuring oxidation resistance are shown in FIG. 2.

As mentioned above, it can be seen that the oxidation resistance of the magnetic recording metal powder is much better than that of the comparative example. It can be seen from FIG. 2 that the addition of Mn, Cu or Zn-containing Mn alloy to the metal (alloy) magnetic powder has an excellent effect of significantly improving the corrosion resistance of the metal magnetic powder.

Claims (3)

200 ml / min flow rate after adding 4.6 N caustic soda solution to a mixed solution containing 0.01 to 2 atomic% Mn ⁺⁺ in a solution of ferrous sulfate containing Fe ⁺⁺ and a mixed solution of manganese sulfate A method for producing magnetic magnetic powder for magnetic recording obtained by air oxidation, dehydration and reduction with air. 4.6 in a mixed aqueous solution of a mixed solution of manganese sulfate and copper sulfate containing 0.01 to 2 atomic% Mn ⁺⁺ and 0.01 to 1 atomic Cu ⁺⁺ in an iron sulfate solution containing Fe ⁺⁺ . A method of producing magnetic magnetic powder for magnetic recording obtained by adding N aqueous solution of caustic soda, followed by air oxidation with air at a flow rate of 200 ml / min, dehydration and reduction. 4.6 to a mixed aqueous solution containing 0.01 to 2 atomic% Mn ⁺⁺ and 0.01 to 1 atomic Zn ⁺⁺ in a solution of iron sulfate containing Fe ⁺⁺ and a mixed solution of manganese sulfate and zinc sulfate A method of producing magnetic magnetic powder for magnetic recording obtained by adding N aqueous solution of caustic soda, followed by air oxidation with air at a flow rate of 200 ml / min, dehydration and reduction.

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