Sakai Chemical Industry Co., Ltd.

Yasuo Araki

Seiji Matsumoto

Hajime Uno

Shoichi Tamura

Masami Nakayama

Shigeki Sato

Shigeharu Higuchi

The invention provides nickel hydroxide secondary particles comprising agglomerates of primary particles of nickel hydroxide in the shape of a triangular prism or a triangular plate having a surface or a outer face in the form of a substantially equilateral triangle each side of which substantially equilateral triangle has a length of 1 to 10 &mgr;m. The invention further provides lithium nickel composite oxide secondary particles comprised of agglomerates of primary particles having a large particle diameter by mixing the nickel hydroxide secondary particles with a lithium compound and sintering the resulting mixture at a temperature of 600&deg; C. to 1000&deg; C. in an oxidative atmosphere.

Nickel hydroxide particles and production and use thereof

A method of producing cobalt-modified magnetic particles is provided. The method comprises heating an aqueous suspension of ferric hydroxide at temperatures of 100.degree.-250.degree. C. at an alkaline pH in the presence of a water soluble organic or inorganic compound capable of forming complexes with iron as a growth regulating agent, and preferably also in the presence of .alpha.-ferric oxide seed crystals of minor axes not larger than 0.4 microns in average in amounts of 0.1-25 mole % in terms of the Fe content thereof in relation to the ferric hydroxide, converting the obtained .alpha.-ferric oxide into .gamma.-ferric oxide by reduction thereof followed by oxidation, maintaining an aqueous suspension of the .gamma.-ferric oxide at temperatures of 30.degree.-50.degree. C. at an alkaline pH in the presence of ferrous hydroxide and cobaltous hydroxide in amounts of 0.5-50 mole %, respectively, in relation to the Fe content of the .gamma.-ferric oxide in the suspension for a length of time sufficient to modify the .gamma.-ferric oxide particles.

Method of producing cobalt-modified magnetic particles

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Sakai, Japan

Yasuo Araki