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

Abstract: Zircon encapsulated carbon (C@ZrSiO₄) black pigment was synthesized via non-hydrolytic sol-gel method, using rice husk powder as carbon source, anhydrous zirconium tetrachloride as zirconium source, tetraethyl orthosilicate (TEOS) as silicon source, lithium fluoride (LiF) as mineralizer, polyvinyl butyral (PVB) as dispersant, respectively. The structure and morphology of rice husk powders and the pigments were studied by using X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscope (SEM) and transmission electron microscopy (TEM), while the chromatic value of the pigments was characterized by CIE-L*a*b* color system. The results show that pure ZrSiO₄ can be prepared by using 200 ℃ dried rice husk as carbon source. The proper weight ratio of carbon to ZrSiO₄ is 3.75 wt.%.Therefore, the C@ZrSiO4 pigment exhibits excellent coloring performance with L*=47.25, a*=0.59, and b*=1.81. The deficiency of rice husk causes the shortage of carbon content, resulting in the poor chromatic performance. However, excessive rice husk hinders the dense coating’s formation, which also causes the high L* value.

Key words: black pigment; NHSG method; zircon; carbon; rice husk