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. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.