Structure and lubricated tribological behavior of silicon incorporated carbon nitride composite films deposited by magnetron sputtering

Silicon incorporated C-N films were prepared by ion beam assisted magnetron sputtering using silicon/graphite composite target. The microstructure of the Si-C-N films was characterized by SEM, XPS, TEM and Raman spectroscopy. Mechanical and lubricated tribological behavior of the films were investigated by the nano-indentation experiments and ball-on-disc tribotest in Hanks solution. With the increase of silicon target fraction (FT-Si), the silicon content steadily increased from 1.8 to 15.8 at.% with a simultaneous decrease in the C content from 78 at.% to 56 at.%. The N content slightly decreased from 25.2 at.% to 19.8 at.%, and silicon and N content is saturated as the FT-Si reaches about 50 at.%. The hardness and elastic modulus increased with the FT-Si, while the average friction coefficient decreased with the FT-Si increase. The C-N films deposited at a FT-Si of 10 vol% show the lowest coefficient of friction of 0.049, and exhibited good mechanical and lubricated tribological properties.