An investigation of angle-dependent optical properties of multi-layer structure pigments formed by metal-oxide-coated mica

The angle-dependent pigments with mica/TiO2/Fe2O3, mica/TiO2/Cr2O3 and mica/TiO2/Co2O3 three-layer structure and with mica/TiO2/Cr2O3/Fe2O3, mica/TiO2/SiO2/Fe2O3 and mica/TiO2/SiO2/Co2O3 four-layer structure were both prepared by the conventional wet chemical method. The obtained pigments were formed by precipitating different ions, such as Cr3+, Fe3+, Co2+ and SiO32- on the pretreated substrates, mica titanium. The comparative optical effects of three-layer and four-layer structure pigments are investigated in detail by using the five angles' spectrophotometer. The results show that the angle-dependent effect and reflection rate of the pigment were improved by the increasing coated layers from three to four-layer structure. The possible mechanism was also discussed in this paper. (C) 2007 Elsevier B.V, All rights reserved.