Abstract: The invention relates to effect pigments having an aluminum core or aluminum alloy core and an aluminum oxide-containing or aluminum oxide/hydroxide-containing layer enveloping said aluminum core or aluminum alloy core, obtained by chemical wet-process oxidation of lamellar aluminum pigments or aluminum alloy pigments, the content of metallic aluminum in the aluminum core or aluminum alloy core being not more than 90% by weight, based on the total weight of the pigment, wherein the oxidized aluminum pigments or aluminum alloy pigments exhibit at least one highly refractive metal chalcogenide layer having a refractive index of >1.95, and a mixed layer is formed between the highly refractive metal chalcogenide layer and the enveloping aluminum oxide-containing or aluminum oxide/hydroxide-containing layer. The invention further relates to a process for the production of such effect pigments and to the use thereof.

Abstract: The invention relates to effect pigments comprising an aluminium core or an aluminium alloy core, and a layer containing aluminium oxide or aluminium oxide/hydroxide surrounding the aluminium core or the aluminium alloy core. Said pigments can be obtained by wet-chemical oxidation of plate-shaped aluminium pigments or aluminium alloy pigments. According to the invention, the content of metal aluminium in the aluminium core or aluminium alloy core is not more than 90 wt. % in relation to the total weight of the pigment. The oxidised aluminium pigments or aluminium alloy pigments contain at least one highly refractive metal chalcogenide layer having a refraction index of >1.95, and a mixed layer is formed between the highly refractive metal chalcogenide layer and the enveloping layer containing aluminium oxide or aluminium oxide/hydroxide. The invention also relates to a method for the production of said effect pigments and to the use thereof.