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

Defect-free Ni-Mo-Si metal suicide coatings with a microstructure consisting of Mo₂Ni₃Si primary dendrites and the interdendritic Mo₂Nl₃Si/NiSi eutectics were deposited on austenitic stainless steel AIS1321 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 Mo₂Ni ₃Si/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.