The effect of carbon fraction in Zr(C, N) films on the nano-structural properties and hardness

The effect of methane flow ratios F(CH4) in a mixture of Ar and N2 gases on the formation of zirconium carboni- tride films deposited by single ion beam sputtering on AISI 304 stainless steel substrates have been investigated. To study this effect on the micro-structure of those films, scanning electron microscopy, X-ray diffraction analyses and Rutherford backscattering were performed. Surface hardness was also measured using a Vickers microhardness tes- ter. The results show that an increase of methane flow ratio leads to a shift of ZrN crystalline phase toward ZrC crystalline phase through an intermediate phase ZrN1-xCx with 0?x?1. The increase of F(CH4) changes also the crys- tallographic texture from (111) to (220). A maximum hardness of 2520 Hv was obtained for x=0.57 which is in ac- cordance with Cohen’s theoretical model.