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

The effect of methane flow ratios F (CH 4) in a mixture of Ar and N 2 gases on the formation of zirconium carbonitride films deposited by single ion beam sputtering on AISI 304 stainless steel substrates has been investigated. To study this effect on the micro-nano-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 tester. 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 ZrN 1− x C x with 0 ≤ x ≤ 1. The increase of F (CH 4) changes also the crystallographic texture from (1 1 1) to (2 2 0). A maximum hardness of 2520 Hv was obtained for x = 0.57 which is in accordance with Cohen's theoretical model.