Structure and tribology of biocompatible Ti–C:H coatings

Ti–C:H coatings with different carbon content for biomedical applications were deposited by PECVD. Ti was varied by magnetron sputtering a Ti-target with different power in a dc discharge regime having Ar in the atmosphere. Ti–C:H coating was tribologically tested reflecting its expected use as an interlayer for improving the adhesion of functional a-C:H coatings. The tribological properties were studied using a pin-on-disc CSM Tribometer in order to ensure stable tribological properties of the whole Ti–C:H/DLC system for any case of top layer failure. The sliding tests were carried out at room temperature in room environment with relative air humidity 40 ± 5%, in 0.9% NaCl water solution (physiological solution, PS) and in 10% fetal bovine serum (FBS) dissolved in Ringer's saline solution using 440C steel balls with a diameter of 8 mm. The variation of the C2H2 flow led to carbon contents in the range [18–91 at.%]. The Ti-rich coatings exhibited poor wear resistance, while the best tribological properties were achieved for TiC/a-C:H coatings deposited with the highest C2H2 flows. When tested in biological solutions, the friction and wear resistance were analyzed with respect to their corrosion propertie