Microstructure and dry sliding wear resistance of laser clad Mo₂Ni₃Si/NiSi metal silicide composite coatings

Mo₂Ni₃Si/NiSi wear-resistant metal silicide composite coatings were fabricated on the 1Cr18Ni9Ti austenitic stainless steel substrate by laser cladding, using Ni-Mo-Si elemental powder blends as the raw materials. The microstructures of the resulting composite coating and its worn surface morphology were analyzed by means of optical microscopy and scanning electron microscopy. The phase composition of the composite coating was examined by means of X-ray diffraction and energy dispersive spectrometry. The friction and wear behavior of the composite coating in sliding against quenched and tempered ASIS1045 steel at ambient condition was evaluated on an MM-200 friction and wear tester. Results indicated that the laser clad Mo₂Ni₃Si/NiSi metal silicide composite coating had fine microstructure consisting of Mo₂Ni₃Si primary dendrites and the interdendritic Mo₂Ni₃Si/NiSi eutectics. The composite coating had excellent dry sliding wear resistance which was improved with the increase of volume fraction of the primary ternary metal silicide Mo₂Ni₃Si. Moreover, the wear mass loss of the laser clad Mo₂Ni₃Si/NiSi metal silicide composite coating was much insensitive to the increase of the applied load.