A study of Ta_xC_(1-x) coatings deposited on biomedical 316L stainless steel by radio-frequency magnetron sputtering

摘要

In this paper, Ta_xC_(1-x) coatings were deposited on 316L stainless steel (316L SS) by radio-frequency (RF) magnetron sputtering at various substrate temperatures (T_s) in order to improve its corrosion resistance and hemocompatibility. XRD results indicated that T_s could significantly change the microstructure of Ta_xC_(1-x) coatings. When T_s was <150℃, the Ta_xC_(1-x) coatings were in amorphous condition, whereas when T_s was >150℃, TaC phase was formed, exhibiting in the form of particulates with the crystallite sizes of about 15-25 nm (T_s = 300 ℃). Atomic force microscope (AFM) results showed that with the increase of T_s, the root-mean-square (RMS) values of the Ta_xC_(1-x) coatings decreased. The nano-indentation experiments indicated that the Ta_xCi_(1-x) coating deposited at 300 ℃ had a higher hardness and modulus. The scratch test results demonstrated that Ta_xC_(1-x) coatings deposited above 150 ℃ exhibited good adhesion performance. Tribology tests results demonstrated that Ta_xC_(1-x) coatings exhibited excellent wear resistance. The results of potentiodynamic polarization showed that the corrosion resistance of the 316L SS was improved significantly because of the deposited Ta_xC_(1-x) coatings. The platelet adhesion test results indicated that the Ta_xC_(1-x) coatings deposited at T_s of 150℃ and 300℃ possessed better hemocompatibility than the coating deposited at T_s of 25℃. Additionally, the hemocompatibility of the Ta_xC_(1-x) coating on the 316L SS was found to be influenced by its surface roughness, hydrophilicity and the surface energy.