ZHANG Xiaojun ¹, CHEN Ting ^{1, 2}, JIANG Weihui ^{1, 2}, LIU Jianmin ², ZHA Jianrui ¹
(1. School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333403, Jiangxi, China;
2. National Engineering Research Center for Domestic and Building Ceramics, Jingdezhen Ceramic Institute,
Jingdezhen 333001, Jiangxi, China)

 Abstract: C@SiO₂@ZrSiO₄ black inclusion pigment was prepared by composite coating method, using zirconium tetrachloride and tetraethoxysilane as precursors, carbon black as colorant, LiF as mineralizer and polyvinyl butyral (PVB) as dispersant, respectively. The effects of ZrSiO₄/C ratios, heat treatment on the synthesis and chromatic value of the pigment were studied by using FTIR, XRD, TEM and CIE-L*a*b* color system. The results show that the carbon black particles can be well coated by SiO₂ and ZrSiO₄ layer, and the SiO₂ layer is beneficial to the connection between carbon black and ZrSiO₄ layer. The optimal ZrSiO₄/C ratio for the synthesis of ZrSiO₄ is 0.85. Too low ZrSiO₄/C ratio influences the synthesis of ZrSiO₄, resulting in the impurities of ZrO₂ and SiO₂. When the ratio is larger than 0.85, the ZrSiO₄ layer is too thick, causing the poor chromatic performance. Heat treatment has a significant effect on the chromaticity. Its CIE coordination is L*=52.37, a*=0.90, b*=2.77, which can be obtained after being heat treated in nitrogen atmosphere at 1000 ℃ for 2 h and then in air at 800 ℃ for 2 h.
Key words: pigment; composite coating; ZrSiO₄; carbon