Preparation of zirconia coated graphite powders

ZrO$_2$ coated flake graphite powders were prepared by the controlled hydrolysis of zirconium oxichloride. The stirring process plays an important role in the coating process. There are two types of coated ZrO$_2$ particles: (a)primary particles with few nm size were obtained by the direct formation of the shell by precipitation of the surface of the graphite and (b) Secondary particles of ZrO$_2$ with ∼0.1$\mu\textrm{m}$ size were obtained by the independent formation of primary particles ZrO$_2$ and subsequent heterocoagulation at the graphites surface.