Deposition of thin TiO₂ films on fluorophlogopite particle surface by CVD in fluidized bed reactor to prepare silver pearlescent pigments

Two critical parameters: Glossiness and chromaticity space of pearlescent pigments were evaluated based on crystallinity and grain size. Both the roughness and the vertical distance evolution along the surface of deposited TiO2 film are affected by the crystallinity. The optimal crystallinity of TiO2 was deposited at the temperature of 350 degrees C. The TiCl4 concentration effectively changed the grain size. However, the high flow rate of fluidizing gas and optimal gas-solid ratio (<0.11 m(3)/(kg h)) restricted the change of TiCl4 concentrations in fluidized bed reactor. In this case, the grain size of the deposited TiO2 film was about 55 nm. Depending on the grain size, the color of pearlescent pigments was adjusted by controlling the film thickness based on TiO2 concentration. Finally, the silver pearlescent pigment with high glossiness was prepared by chemical vapor deposition method in a fluidized bed reactor.(c) 2023 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.