Physical, chemical and biological properties of micro-arc deposited calcium phosphate coatings on titanium and zirconium-niobium alloy

A comparative investigation of the physical, chemical and biological properties of micro-arc deposited calcium phosphate coatings on titanium and zirconium-niobium substrates was performed. Calcium phosphate coatings on titanium have a higher surface density, porosity and pore size, and a more homogeneous surface topography. Under the same conditions, calcium phosphate coatings on zirconium-niobium have a relief topography, but their surface density, porosity and pore size were all smaller. X-ray diffraction of the coatings showed that the coatings on titanium were X-ray amorphous whereas the coatings on zirconium-niobium consisted of a mixture of crystalline CaZr4(PO4)(6), ZrP2O7, and ZrO2. These differences are due to different electrical and thermophysical characteristics of substrates and passivating films on their surfaces. The coatings were shown to be biocompatible by in-vitro cell culture experiments.