Effect pigments based on Al.sub.2O.sub.3 flakes with high weather resistance and less photoactivity and to their use thereof in paints, industrial coatings, automotive coatings, printing inks, cosmetic formulations. The effect pigments have a ratio of the amount by weight of Al.sub.2O.sub.3 of the Al.sub.2O.sub.3 flake and the amount by weight of the metal oxide(s) of the coating layer(s) in the range of from 27:73 to 83:17 based on the total weight of the effect pigment.

Effect pigments based on Al.sub.2O.sub.3 flakes with high weather resistance and less photoactivity and to their use thereof in paints, industrial coatings, automotive coatings, printing inks, cosmetic formulations. The effect pigments have a ratio of the amount by weight of Al.sub.2O.sub.3 of the Al.sub.2O.sub.3 flake and the amount by weight of the metal oxide(s) of the coating layer(s) in the range of from 27:73 to 83:17 based on the total weight of the effect pigment.

Effect pigments based on Al.sub.2O.sub.3 flakes with high weather resistance and less photoactivity and to their use thereof in paints, industrial coatings, automotive coatings, printing inks, cosmetic formulations. The effect pigments have a ratio of the amount by weight of Al.sub.2O.sub.3 of the Al.sub.2O.sub.3 flake and the amount by weight of the metal oxide(s) of the coating layer(s) in the range of from 27:73 to 83:17 based on the total weight of the effect pigment.

Effect pigments based on Al.sub.2O.sub.3 flakes with high weather resistance and less photoactivity and to their use thereof in paints, industrial coatings, automotive coatings, printing inks, cosmetic formulations. The effect pigments have a ratio of the amount by weight of Al.sub.2O.sub.3 of the Al.sub.2O.sub.3 flake and the amount by weight of the metal oxide(s) of the coating layer(s) in the range of from 27:73 to 83:17 based on the total weight of the effect pigment.

Effect pigments based on Al.sub.2O.sub.3 flakes with high weather resistance and less photoactivity and to their use thereof in paints, industrial coatings, automotive coatings, printing inks, cosmetic formulations. The effect pigments have a ratio of the amount by weight of Al.sub.2O.sub.3 of the Al.sub.2O.sub.3 flake and the amount by weight of the metal oxide(s) of the coating layer(s) in the range of from 27:73 to 83:17 based on the total weight of the effect pigment.

Effect pigments based on Al.sub.2O.sub.3 flakes with high weather resistance and less photoactivity and to their use thereof in paints, industrial coatings, automotive coatings, printing inks, cosmetic formulations. The effect pigments have a ratio of the amount by weight of Al.sub.2O.sub.3 of the Al.sub.2O.sub.3 flake and the amount by weight of the metal oxide(s) of the coating layer(s) in the range of from 27:73 to 83:17 based on the total weight of the effect pigment.

In order to provide pigment particles and coating compositions comprising them that are suitable for demanding industrial protective coatings and coatings in the automobile sector, a proposal is made for pigment particles having a surface coating for use in a stratifying coating composition, where the surface coating of the pigment particles is formed using an organic, amino-functional component, which in particular has two or more amino groups, and a reactive, silane-functional component different from the aforesaid component.

The present invention relates to weather-resistant pearlescent pigment, comprising a coated or uncoated platelet-shaped substrate which is selected from the group consisting of synthetic mica platelets, glass platelets, SiO.sub.2 platelets, Al.sub.2O.sub.3 platelets, synthetic boehmite platelets, BiOCl platelets and mixtures thereof, a chromophoric coating with at least one highly refractive metal oxide, and a top layer, wherein the top layer comprises the following layer sequence:
a) a first layer made of tin oxide and/or tin hydroxide and/or hydrated tin oxide, b) a second cerium-containing layer which comprises cerium oxide and/or cerium hydroxide and/or hydrated cerium oxide, c) an organic-chemical coating applied to the cerium-containing layer which contains oligomeric silanes or consists of them, wherein the oligomeric silanes have one or more amino groups and the oligomeric silanes are chemically bonded with the cerium-containing layer. The invention further relates to a process for the production and use of these pearlescent pigments.

Interference pigments based on SiO.sub.2 flakes coated with crystallites of alpha-Fe.sub.2O.sub.3. Also, a process for the preparation of interference pigments that comprise SiO.sub.2 flakes coated with a crystallite of alpha-Fe.sub.2O.sub.3, by a wet-chemical process in a fluidised bed, by a CVD process, by a PVD process, or by any combination of said processes. Also, the use of interference pigments based on SiO.sub.2 flakes coated with crystallites of alpha-Fe.sub.2O.sub.3, in particular in paints, coatings, industrial and automobile paints, ceramic materials, plastics and cosmetic formulations.