MECHANICAL AND TRIBOLOGICAL BEHAVIOR OF VN AND HfN FILMS DEPOSITED VIA REACTIVE MAGNETRON SPUTTERING

Abstract

HfN and VN thin films were deposited onto silicon and 4140 steel substrates with r.f. reactive magnetron sputtering by using Hf and V metallic targets with 4-inch diameter and 99.9% purity in argon/nitrogen atmosphere, applying a substrate temperature of 250°C and a pressure of 1.2 × 10-3 mbar. In order to evaluate the structural, chemical, morphological, mechanical and tribological properties, we used X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM), scanning electron microscopy (SEM), nanoindentation, pin-on-disc and scratch tests. Film structure determined by XRD showed that FCC ( NaCl -type) films are formed in both the cases by δ- HfN and δ- VN phases. Hardness and elastic modulus values obtained for both the films were 21 and 224 GPa for the HfN film and 19 and 205 GPa for the VN film, respectively. Additionally, the films showed low friction coefficient of 0.44 for HfN and 0.62 for VN when these films were evaluated against 100 Cr 6 steel, and finally the critical load was found at 41 N for the HfN film and 34 N for the VN film.