Wear behavior and microhardness studies of tantalum (Ta)-coated 316L stainless steel by DC magnetron sputtering for the orthopedic applications

The lack of resistance to wear of the biomaterials and release of ions cause implant loosening, which leads to implant failure. As a result, surface modification of such biomaterials (316L SS) is required to ensure implant durability. To improve the wear resistance and durability of the implant, the Ta layer was deposited on 316L SS, and film quality can be enhanced by having excellent control of parameters during deposition. Metallic coating (Tantalum) was applied on the surface of stainless steel type 316L by DC magnetron sputtering, followed by wear behavior and microhardness investigations. Wear studies through pin-on-disk tribometer are used to evaluate tribological properties, i.e., wear rate and friction coefficient behavior following ASTM G99-95a and ASTM G133-95. Wear tests were conducted in simulated body fluid under various normal applied load conditions (10 N, 20 N, and 40 N) and a sliding distance of 10 m. Based on wear test results, the wear rate (62.50 x 10(-5) mm(3)/Nm) was found to be very high for bare 316L SS at an applied load of 40 N, and the wear rate (3.75 x 10(-5) mm(3)/Nm) was found to be low for Ta-coated (60 min.) 316L SS at the same load. Wear-resistant and surface hardness of Ta-coated 316L SS were found to increase with an increase in the thickness of the coating. Ta-coated was found to be a higher hardness and lower modulus of elasticity against bare 316L SS. Optical microscopy, scanning electron microscopy, energy-dispersive X-ray analysis, and atomic force microscopy were used to characterize the surface morphology of worn bare and Ta-coated 316L SS. This study aims to see how Ta-based coatings could be used to improve the surface morphology of austenitic stainless steel.