Microstructure and tribocorrosion performance of nanocrystalline TiN graded coating on biomedical titanium alloy
(1. Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Material Science and Engineering, Northeastern University, Shenyang 110819, China;
2. QC Department, Goertek Inc., Weifang 261000, China)
2. QC Department, Goertek Inc., Weifang 261000, China)
Abstract: A nanocrystalline TiN graded coating was prepared on Ti6Al4V alloy by DC reactive magnetron sputtering method. The microstructure and mechanic properties of the coating were investigated. The electrochemical corrosion and tribocorrosion of the coated specimens in physiological environment were compared with those of Ti6Al4V substrate. The results show that the gradient distribution of nanocrystalline TiN is favorable for releasing the inner stress in the coating, which increases adhesion strength to 90 N. The compact structure and refined-grains of the coating result in the surface nanohardness of 28.5 GPa. The corrosion protection efficiency of the nanocrystalline TiN coating reaches 96.6%. The tribocorrosion resistance of the coating increases by 100 times in comparison with that of Ti6Al4V substrate. The high chemical stability and H3/E2 ratio (where H is hardness, and E is elastic modulus) of the nanocrystalline TiN coating are responsible for good corrosion and wear resistances.
Key words: TiN coating; nanocrystalline; hardness; adhesion; tribocorrosion performance