HEAT STABLE IRON OXIDE PIGMENTS OF –-FE O STRUCTURE, A PROCESS FOR THEIR PRODUCTION AND THEIR USE

摘要

HEAT-STABLE IRON OXIDE PIGMENTS OF .gamma.-Fe2O3 STRUCTURE, A PROCESS FOR THEIR PRODUCTION AND THEIR USE A pigment useful for coloring building materials such as bricks is a heat-stable isometric iron oxide brown pigment of .gamma.-Fe2O3 structure which has a silicon content, expressed as SiO2, of 0.1 to 12% and an Al content, expressed as Al2O3, of 0.02 to 5%.