Effect of nitrogen content on the mechanical and biological properties of tantalum nitride coatings

Abstract

In this article, the effect of nitrogen content on the mechanical and biological properties of Tantalum Nitride coatings has been studied. TaN coatings with different N concentrations were deposited on glass slides and medical metals by magnetron sputtering in Ar + N2 atmosphere to improve the adhesion strength and biocompatibility of PVD coatings. The morphology, composition, mechanical properties, and biology of the TaN films were characterized at varying N levels, which were obtained by adjusting the flow rate of N2 at 5, 10, and 15 sccm. Results showed that hardness of the coating increased when N2 was added. The film transitioned from γ-Ta2N to ε-TaN and δ-TaN when N2 gas flow rate increased. The γ-Ta2N coating had the highest hardness (37.30 GPa). The adhesion strength of the coatings was increased with N2 flow rate and then decreased, the ε-TaN film deposited at a N2 flow rate of 10 sccm had the highest adhesion strength (18.12 N). TaN coating deposited at a N2 flow rate of 10 sccm showed the highest cell growth rate (151.77 %) and number of cells on the surface. The friction curve of the δ-TaN coating subjected to 15 sccm N2 flow rate exhibited excellent wear resistance with minimum fluctuation. According to the aforementioned findings, TaN coatings deposited under various nitrogen flow rates have significantly improved in adhesion strength, wear resistance, hardness, and biocompatibility, which offers a good reference value for research on the surface modification of medical metal and a good replacement material for the field of medical implantation.