Influence of Slight Pressure Variations on the Mechanical and Tribological Properties of Ti/TiAlV/TiAlVN Coatings Produced by Magnetron Sputtering

Abstract

Ti/TiAlV/TiAlV(N) coatings were deposited by D.C magnetron sputtering technique. This experiment was carried out on 316L stainless steel substrates, and it was produced varying the working pressure, in an environment composed by a mixture of Ar/N2. While Ti and TiAlV layers were produced at a constant pressure, TiAlV(N) layers were grown at 0.6, 0.8, 0.9 and 1.0 Pa, for samples M1, M2, M3 and M4, respectively. After the production, morphological, compositional and structural properties of coatings were studied using techniques as x-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and atomic force microscopy (AFM). Next, mechanical and tribological properties such as hardness, Young’s modulus, coefficient of friction, and adherence were evaluated, using nanoindentation, scratch test and ball on disc methods. XRD analysis evidenced that coatings crystallized in a salt rock FCC structure, and the crystallite size tended to increase with the increase of pressure. The XPS analysis allowed to demonstrate the presence of the doublets corresponding to metallic aluminum. Titanium was also found as well as the presence of oxygen as an oxidizing element of the coating.  Regarding to the morphological analysis, it was observed an increase of the roughness when the coatings were grown, compared with the stainless substrates; moreover, no significant influence of the small pressure variation was observed on properties as hardness, coefficient of friction, and critical load.