Role of nickel in structural and mechanical properties of nc-WNNi sputtered nanocomposite coatings

Abstract

Nanocomposites coatings offers a wide range of possibilities to promote hardness, oxidation resistance, wear resistance, etc properties significant for protective coatings. Finding new nanostructured coating with high hardness and thermal stabilities are the prime requirement of modern industries. In view of above, the nc-WNNi nanocomposite coatings were deposited using reactively sputtered method on silicon (100) substrate by varying the power of Nickel (Ni). The coatings were characterized by using grazing incidence X-ray diffraction (GIXRD), Field emission scanning electron microscope (FESEM), energy dispersive x-ray analysis (EDX), thickness profiler, four probe resistivity measurement and nanoindentation tester. Through GIXRD studies the desired face centered cubic W2N phase was confirmed, with decreasing crystallite size on increasing Ni power (content). FESEM image revels/suggest that at low Ni content, the film structure stabilized into well separated grains with the presence of grain boundary and were of uneven shape throughout. On increasing Ni power, the agglomeration increase and no clear signature of grain boundaries were visible. The resistivity of the films was found to be decreasing with increasing Ni content at different temperatures. Improved mechanical properties were observed at low Ni power (content), which drastically decreases with increasing Ni power. The highest hardness (H), elastic modulus (Er), elastic recovery (We), and resistance to plastic deformation (H-3/E-2) were obtained 26.60 GPa, 276.82 GPa, 69.80 GPa, 245 MPa respectively for nc-WN10Ni film. The nc-WN10Ni film shows the highest mechanical properties as compared to others.