Evolution of microstructure and properties in laser cladding of a Ni-Cr-B-Si hardfacing alloy

Ni-Cr-B-Si coatings are used in many industrial applications in order to improve wear and/or corrosion properties. These coatings have traditionally been deposited by thermal spray techniques but the laser cladding process is also being increasingly employed to produce Ni-Cr-B-Si coatings with superior functional properties. In this research, the microstructural evolutions and the phase formations in the laser cladding of a Ni-Cr-B-Si alloy and their effects on the hardness of the clad layer are discussed. Results of this study show various types of boride and carbide phases can form in each track of the clad layer. These changes demonstrate the potential for tuning the properties of these coating by controlling the processing conditions. © 2011 WIT Press