| abstract |
A platelet-shaped two-phase pigment consists of a core with a hematite structure of the composition Al x Fe 2-x O₃, wherein x has a value of 0.02 to 0.5 and an outer layer with spinel structure with the composition Al y Fe 3-y O 4 + z , where y has values from 0.03 to 0.75 and z has values from 0 to 0.5.n n n The pigments can be prepared by hydrothermal treatment of platelet-shaped Al x Fe 2-x O₃ pigments (with x values from 0.02 to 0.5) in the presence of a reducing agent dissolved in the aqueous phase. |