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

Liu, M., Shao, G., Lv, P., Li, J., & Zhu, Q. (2024). Deposition of thin TiO2 films on fluorophlogopite particle surface by CVD in fluidized bed reactor to prepare silver pearlescent pigments. Particuology, 89, 88-98. https://doi.org/10.1016/j.partic.2023.10.005

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

Ming Liu ^a, Guoqiang Shao^a, Pengpeng Lv ^a, Jun Li ^{a b}, Qingshan Zhu ^{a b *}

a State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
b School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China

10.1016/j.partic.2023.10.005

Volume 89, June 2024, Pages 88-98

Received 1 August 2023, Revised 15 October 2023, Accepted 15 October 2023, Available online 2 November 2023, Version of Record 6 December 2023.

E-mail: qszhu@ipe.ac.cn

Highlights

• TiO₂ films with high crystallinity show sharp surface and poor glossiness.

• The grain size can be decreased only when largely increasing the TiCl₄ concentration.

• Free particles attached on the surface of pearlescent pigment decreased with gas–solid ratio.

• The color of pearlescent pigment can be changed by film thickness and grain size.

Abstract

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 °C. The TiCl₄ concentration effectively changed the grain size. However, the high flow rate of fluidizing gas and optimal gas–solid ratio (<0.11 m3/(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.

Graphical abstract

Keywords

Fluidized bed chemical vapor deposition; TiO₂ film deposition; Pearlescent pigment; Free powder restrain; Crystal growth

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