Improving the Biocompatibility Performance of Ti-6Al-4V Alloy with Bi Phasic Calcium Phosphate Gradient Coating By Plasma Spray Method

Due to the problems of metal implants, it is observed that one of the main techniques in solving these problems is to improve the properties of implant coatings. One of the coatings that has been considered in the last decade is biphasic calcium phosphate gradient coating. Plasma spraying method was used to coating the implants and three coating layers including HAp, TCP 50%-HAp 50% and TCP were applied gradient on the titanium substrate, respectively. X-ray diffraction test was used to identify the phases. Corrosion of the applied layers was performed using body simulation solution and open circuit potential electrochemical tests were used to evaluate the corrosion of coating. Field emission scanning electron microscopy was used to observe the morphology and thickness of the layers before and after being placed in the body simulation solution. According to the results of open circuit corrosion potential test, the corrosion voltage is -0.07, -0.09 and -0.19 V for the sample with one layer of HAp coating, the sample without coating and the sample with three layers of coating HAp, TCP 50%-HAp 50% and TCP were obtained respectively. By placing the three-layer coating in SBF solution, tricalcium phosphate in the third and second layers is completely dissolved and with the presence of calcium and phosphorus ions in the form of saturated secondary hydroxyapatite is formed inside the coating.