Preparation and characterization of ZrO₂ modified CaO SiO₂ bio-composite coatings

CaO stabilized ZrO₂ powders were calcined with certain content of SiO₂ at 1400℃, the obtained powders were used to fabricate coatings with different Ca₂SiO₄ contents (mass fraction: 20％, 40％, 60％) by atmospheric plasma spraying technology. The morphology and phase composition of the ZrO₂ modified CaO-SiO₂ coatings were characterized by X-ray diffraction (XRD), electronic probe microanalyzer (EPMA) and energy dispersive spectrometry (EDS). The composite coatings were immersed in simulated body fluid (SBF) and Tris-HCl buffer solution for the in vitro appraisement of bioactivity and stability. The results show that the formation ability of apatite on the surface of the coatings is related with Ca₂SiO₄ content in the coatings. The apatite precipitation becomes difficult on the coating’s surface with Ca₂SiO₄ content lower than 40％. The dissolution rate of the coatings in Tris-HCl solution increases with increase of Ca₂SiO₄ content.