Structure and tribological properties of Ti-containing amorphous carbon coatings prepared by cathode arc-enhanced middle-frequency magnetron sputtering

Ti-containing amorphous carbon （Ti-aC） coatings were deposited on cemented carbide and Si substratcs by cathode-arc-enhanced closed field middle-frequency unbalanced magnetron sputtering. The coatings were studied by using atomic force microscopy, Raman scattering, nanoindentation, and pin-on-disk testing. The measurements showed that the hardness of the coatings increased from 12 GPa at a Ti content of 1 at.% to 27 GPa at 31 at.%. The coatings exhibited different friction behaviors when facing different mating materials and changed with increasing Ti content, The coating with 4 at.% Ti exhibited excellent tribological performance with a low friction coefficient of 0.07 when facing the cemented carbide.