A novel process has been developed to improve tribological and corrosion properties of austenitic stainless steel (S. S). Titanium nitride coatings were obtained by plasma surface alloying technique. Nitrogen-doped titanium dioxide was synthesized by oxidative annealing the resulted TiNx coatings in air. The microstructure of TiO2coatings was characterized by SEM, GDOES, XPS and XRD, respectively. Simulated body solution (Hanks’ solution, 37°C) was used to characterize the electrochemical corrosion properties of the coatings and substrate. Ball-on-disc sliding wear was applied to test and compare the tribological behaviors of the coatings and substrate against Al2O3ball. Results reveal that the resultant coatings have a layered structure, comprising of N-doped TiO2layer at the top and a diffuse-type interface. Such a hybrid coatings system shows good adhesion with the substrate. Composition analysis shows that the coatings shield the substrate entirely. The N-doped TiO2coatings are anatase in structure as characterized by X-ray diffraction. The electrochemical measurements show that the corrosion potential positively shifts from -0.267 V for bare S. S to -0.275 V for N-doped TiO2coated S. S, and the corrosion current density decreases from 1.3 × 10-5A/cm2to 4.1 ×10-6A/cm2. Under a load of 7.6 N, the coefficient of friction is in the range of 0.27～0.38 for the N-doped TiO2and the wear rate of the coatings is only one-fourteenth of that for untreated 316L S. S. Duplex-treated N-doped TiO2coatings display much better wear resistance and antifriction performance than that of S. S.
Preparation, Microstructure, Mechanical Properties and Biocompatibility of Ta-Coated 3Y-TZP Ceramic Deposited by a Plasma Surface Alloying Technique
