Magnetic particle mfg. method, magnetic particle and magnetic recording medium

Abstract

To manufacture alloy particles which satisfy the requirement of fine size, single dispersion and easy form changing in an alloy particle producing process. A solution L1 is injected through a first nozzle 34 into a mixture chamber 20 at the high-pressure jet stream of 1MPa or higher as a disturbed flow in which Reynolds number is 10000 or higher at the time of flowing into the mixture chamber 20, a solution L1 lower in pressure than the solution L1 is injected through a second nozzle 36 into the mixture chamber 20 as a flow roughly orthogonal to the solution L1, the two solutions are mixed to react, and thus a mixed reaction solution LM containing alloy particles is formed.

Description

technical field [0001] The present invention relates to a method for producing magnetic particles, magnetic particles, and a magnetic recording medium including the magnetic particles in a magnetic layer. Background technique [0002] It is important to reduce the particle size of the magnetic particles contained in the magnetic layer in order to increase the magnetic recording density. For example, in magnetic recording media widely used as video tapes, computer tapes, magnetic disks, etc., when the mass of hard magnetic materials is the same, the smaller particle size receives less noise. [0003] As a magnetic particle material that is expected to increase the magnetic recording density, CuAu type or Cu 3 Au-type hard magnetic ordered alloy (such as: Patent Document 1, Patent Document 2). It is known that such a hard magnetic ordered alloy exhibits hard magnetism even if the particle size of the magnetic particles is reduced because the crystal magnetic anisotropy incre...

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Problems solved by technology

[0013] However, in the past, in the process of producing alloy particles by a mixing reaction device, due to the existence of a quiet zone in the container 2, the stirring of the solution was not uniform enough, and the generated alloy particles might grow in the container 2 by local circulation, so it was impossible to produce Alloy particles with small size, good monodispersity and excellent phase changeability

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