Zirconia is mainly used as an implant material; however, due to bioinertness, problems, such as falling off or shaking, during implant placement arise. In this study, the bioactivity of zirconia was improved by coating the zirconia substrate with a wollastonite slurry. Suitable wollastonite slurry was prepared for spin coating by controlling the solid loading, pH, and dispersant. The surface properties of the wollastonite-coated layer, i.e., microstructural evolution, surface morphology, roughness, and phase composition, were dependent on the coating thickness, which are directly related to the number of coating cycles. The valuable wollastonite-coated layer was fabricated on the 3Y-TZP substrate by repeating the coating cycle more than four times. The wollastonite-coated layer comprised an α-phase with a porous structure, and its surface roughness increased by more than 10 times for the as-sintered 3Y-TZP substrate. The improvement in the bioactivity of the 3Y-TZP substrate by wollastonite coating was confirmed by the results obtained from in vitro test. During the immersion of the SBF solution, wollastonite dissolution and precipitation of hydroxyapatite particles were observed on the coated surface, indicating that the wollastonite surface coating contributed to the improvement in 3Y-TZP bioactivity

Keywords: Wollastonite Coating, Zirconia Substrate, Slurry and Spin Coating