Mitsui Minings & Melting Co., Ltd.

Koichi Katsuyama

Shoichi Fujiyasu

Hiroyuki Shimamura

Takashi Nakashima

Tomio Hayashi

Tomoyuki Hoshino

Disclosed is a composite black oxide particle which is composed of oxide of cobalt, copper and manganese. The copper/cobalt molar ratio is 0.1-0.5, and the manganese/cobalt molar ratio is 0.2-1.0. The composite black oxide particle further contains silicon, and the silicon content to the total oxide particle is 0.1-3 mass %. The surface of the composite black oxide particle is coated with aluminum oxide. The Al content in the surface coating to the entire particle is 0.05-3 mass %.

Composite black oxide particle, method for producing same, black coating material and black matrix

Disclosed is a black pigment having adequate degree of blackness and high electrical resistance at the same time. Specifically disclosed is a granular black pigment containing cobalt which is characterized in that it is composed of an oxide containing at least cobalt and the divalent cobalt content accounts for 40-70% of the total cobalt content. It is preferable that the total cobalt content in a whole particle is 60-80% by mass, and the divalent cobalt content in a whole particle is 20-50% by mass. It is also preferable that the primary particle diameter is 0.02-0.6 &#x3bc;m.

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Okayama, Japan

Koichi Katsuyama