Abstract: The complex oxide particles of the present invention are conductive and exhibit a black color. The particles contain cobalt in an amount of 40 to 65% by mass in terms of the metal element based on the whole particles and at least one kind or two or more kinds of metals selected from copper, nickel and molybdenum. The particles are preferably prepared in the following manner: an aqueous solution of mixed metal salts prepared from water-soluble salts, wherein the aqueous solution contains cobalt and one kind or two or more kinds of metal element selected from copper, nickel and molybdenum, is mixed and neutralized with an alkali hydroxide to obtain a metal hydroxide slurry; the resultant slurry of metal hydroxides is kept at a pH of 10 to 13 and oxidized at a temperature of higher than 40° C. and 60° C. or less to obtain a precursor slurry; the resultant precursor slurry is aged at 80 to 150° C.; and then, after solid-liquid separation, the resultant solid is heated at 400 to 700° C.

Abstract: 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 %.

Abstract: 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 ?m.

Abstract: 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 ?m.

Abstract: 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 %.