Black Complex Oxide Particles, Process for Producing the Same, Black Pastes, and Black Matrixes

摘要

The complex oxide particles of the present invention have a black hue, and contains 35 to 70% by weight of cobalt and 5 to 40% by weight of manganese. The molar ratio of cobalt to manganese Co/Mn is 0.5 to 14. The average particle diameter of primary particles is 0.05 to 0.3 mum. The particles have a shape of octahedral form. The particles are produced preferably through wet oxidation. No firing process is performed. The particles contain substantially no metal elements other than cobalt and manganese. The complex oxide particles of the present invention are suitably used as a black pigment for coating material, ink, toner, and rubbers or plastics.