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 CaZr ₄(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.