The effect of plasma spray current on the characterizations and properties of HA-Nb composite coatings and corrosion behavior of 316L substrate

Bio metals have been used for curing bone and join illnesses for years. 316L stainless steel has been used comprehensively as a bio metals because of its lower price in comparison to other bio metals, however its lower corrosion resistance in biological media caused some problems in the body. This studie’s aim is to design and prepare a novel HA-Nb composite coating and study the effect of different electrical current plasma spray intensities to produce coating on 316L stainless steel, in order to find the optimum condition for the plasma spray process. Heat treatment has been done in humid and pure argon media for eliminating unsuitable phases and increasing crystalinity of the coating which was produce at 600A by the plasma spray process. X-ray diffraction and scanning electron microscopy techniques were utilised to investigate the characteristics of coatings. Electrochemical polarization tests were carried out in the physiological ringer solution in order to evaluate the corrosion behavior of coated and uncoated specimens which were done in 400,600 and 800 A plasma spray current intensities. Results indicated that the optimum electrical current intensity for deposition of the HA–Nb composite coating on 316L SS substrate was 600 A. In this condition, corrosion intensity was 120 nA/Cm2 and XRD and SEM results exhibited good structural properties which in turn increased biocompatibility of, 316L SS substrate. In addition heat treatment at 600 oC in the humid media caused the eliminating of tricalcium phosphate which is considered to be an unsuitable phase in the coating.