Microstructure and mechanical properties of SiCN hard films deposited by an arc enhanced magnetic sputtering hybrid system

SiCN hard films have been synthesized on stainless steel substrates by an arc enhanced magnetic sputtering hybrid system using a silicon target and graphite target in mixed gases of Ar and N2. The XRD results indicate that basically the SiCN films are amorphous. However, the HR-TEM results confirm that the microstructure of the SiCN films with a high silicon content are nanocomposites in which nano-sized crystalline C3N4 hard particles are embedded in the amorphous SiCN matrix. The hardness of the SiCN films is found to increase with increasing silicon contents, and the maximum hardness is 35 GPa. The SiCN hard films show a surprising low friction coefficient of 0.2 when the silicon content is relatively low.