Dry sliding wear behavior of laser clad Mo2Ni3Si/NiSi metal silicide composite coatings

Defect-free Ni-Mo-Si metal silicide coatings with a microstructure consisting of Mo2Ni3Si primary dendrites and the interdendritic Mo2Ni3Si/NiSi eutectics were deposited on austenitic stainless steel AISI321 by laser cladding. Wear resistance of the coating is evaluated on pin-on-disc metallic dry sliding wear tester as functions of contact stress and sliding speed. The Mo2Ni3Si/NiSi coatings have excellent wear resistance under dry sliding wear test conditions. Wear mass loss of the coating is nearly invariant with the increasing applied contact stress and sliding speed when subjected to a fixed total sliding distance of 900 m, whereas that of the austenitic stainless steel AISI321 increases drastically with increasing contact stress and sliding speed. Worn surface of the Mo2Ni3Si/NiSi intermetallic coatings has an unique “non-adhesion” feature characterized by its very clean and smooth surface similar to a polish and etched metallographic section.