TiO_2表面包覆SiO_2和Al_2O_3的机理和结构分析

Mechanism and Structure Analysis of TiO 2 Surface Coated with SiO 2 and Al 2O 3

在二氧化钛的表面上包覆一层保护膜，使二氧化钛的表面和周围介质之间产生屏障，从而降低二氧化钛的光化学活性，有利于提高二氧化钛的分散性、耐光性、耐候性和抗粉化性．影响颗粒包膜均匀性和致密性的主要因素是颗粒的分散、加料方式、溶液的酸度和陈化时间等．包膜的均...

Photochemical activity of TiO 2 can be reduced through surface coating, which favors to increase dispersiveness, weather resistance and antipulverization. The binary coating process of Si and Al to TiO 2 was studied experimentally. The isoelectic point of TiO 2 in seriflux was measured as pH was equal to 3 6. Maximum Zeta potential can be got at pH 10 around, which favors to dispersion of particles. Studies on the aggregation rate of Si and Al indicate that, when pH has a value between 9 and 10, the aggregation rate of silicon acid is small, which favors to form homogeneous and compact membrane, so optimal coating pH value is between 9 and 10. According to the difference of 2 p orbital electron binding energy of Ti in XPS before and after being coated, it can be inferred that Si and Al in coating layer combine to TiO 2 surface through chemical bond.