Preparation of Ni–W–Si3N4 composite coatings and evaluation of their scratch resistance properties

In this study, Ni–W–Si3N4 nanocomposite coatings have been prepared by codeposition of Si3N4 nanoparticles into Ni–W alloy coatings having different W contents. The surface morphology and elemental contents in the alloy composite coatings have been analyzed by scanning electron microscopy coupled with EDS. Structure and phase composition were evaluated by using X-ray diffraction (XRD). Progressive type of scratch test was carried out by the scratch tester using a diamond indenter. Results indicated that Vickers microhardness of the Ni–W–Si3N4 composite coatings is found to be higher in comparison to the corresponding Ni–W coatings. In addition, a small increase in Vickers microhardness was observed in Ni–W coatings with higher content of tungsten. Apart from that, a significant influence had been found on scratch resistance properties with the codeposition of Si3N4 and variation of W contents in Ni–W–Si3N4 nanocomposite coatings. Ni–W–Si3N4 nanocomposite with 12.7 at% W and 2.1 wt% Si3N4 has shown improved scratch resistance among others.