Coated magnetic powder and a bonded permanent magnet composition containing the same
AssigneeDaihachi Chemical Industry Co., Ltd.
InventorsHiroshi Yamanaka, Yasuhiro Nakamura
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Abstract
There is provided a surface-treated magnetic powder that can form a resin-bonded permanent magnet with large magnetic force and a high maximum energy product, which magnetic properties do not decrease even after the long periods of time. The surface-treated magnetic powder is obtained by treating a magnetic powder made of an alloy that comprises a rare earth metal and iron with a treatment agent containing a alkali-modified silica particles as a major component, wherein the alkali-modified silica particles are obtained by reacting silica particles with a mean particle diameter of from 0.005 to 0.1 .mu.m with an alkali to modify only the surface portion of the silica particles by the alkali.
Claims11
A coated magnetic powder obtained by coating a magnetic powder made of an alloy that comprises a rare earth metal and iron with an agent containing alkali-modified silica particles obtained by reacting silica particles with a mean particle diameter of from 0.005 to 0.1 .mu.m with an alkali to modify the surface portion of said silica particles by said alkali.
Dependencies are inferred from the claim text.