Evolution of zirconia coating layer on rutile TiO2 surface and the pigmentary property

Zirconia-coated rutile TiO2 composites were prepared by the chemical liquid deposition method starting from rutile TiO2 and ZrOCl2. The amorphous zirconia coating layers were anchored at the TiO2 surface via Zr–O–Ti bond. The formation of continuous and dense zirconia coating layers was dependent on the pH value of the reaction solution and the mole ratio of ZrOCl2 to TiO2. As compared to the naked rutile TiO2, the water dispersibility, whiteness, brightness, and relative light scattering index of the zirconia-coated rutile TiO2 composites were increased.