Electrochemical behavior of cold sprayed hydroxyapatite/titanium composite in Hanks’ solution

A novel approach-cold spraying technique has been successfully used to deposit HAP/Ti composite coating on titanium substrate. The electrochemical corrosion behavior of cold sprayed 20 wt% and 50 wt% HAP/Ti composite coating has been evaluated in a simulated biomedical environment. X-ray diffraction (XRD) analysis and scanning electron microscopy were applied to identify the phases and the morphologies of the coatings. Potentiodynamic polarization and EIS techniques were used to analyze the corrosion behavior in Hanks’ solution. The microhardness measurements and shear punch tests were also conducted to investigate the mechanical property. It was found that cold sprayed 20 wt% HAP/Ti coating showed relatively higher corrosion current than pure Ti and 50 wt% HAP/Ti coating in Hanks’ solution, which indicates a low corrosion resistance. However, the post spray heat treatment improved the corrosion and mechanical properties remarkably. The results obtained in the present work demonstrate suitability of cold spraying technique to manufacture HAP/Ti composite coating on titanium substrate as load-bearing implant material for biomedical applications.