Two-phase pigment in flake form

摘要

A flake-form (leaf) two-phase pigment consists of a core with a haematite structure of composition AlxFe2-xO3, in which x has a value of 0.02 to 0.5, and an outer layer with a spinel structure of composition AlyFe3-yO4+z, in which y has values from 0.03 to 0.75 and z has values from 0 to 0.5. The pigments can be prepared by a hydrothermal treatment of AlxFe2-xO3 pigment flakes (where x is from 0.02 to 0.5) in the presence of a reducing agent which is dissolved in the aqueous phase.