Mechanical and microstructural properties of NiCrFeSiBC/Cr3C2 composite coatings – part I

Abstract

NiCrFeSiBC/Cr3C2 composite coatings were developed on to GrA1 boiler steel by high velocity oxy fuel spray process. The aim was to develop the novel composite coating by finding optimum concentration of Cr3C2 in NiCrFeSiBC matrix, which further possesses the superior solid particle erosion resistance. The mechanical and microstructural properties of the developed coatings were critically examined. The as sprayed coatings were characterised by X-ray diffraction, SEM/energy dispersive spectroscopy analyses. The coatings exhibited characteristic splat-like morphology with the presence of micropores, unmelted and semimelted particles and inclusions. The adhesion strength of the developed coatings was also determined. The physical properties like surface roughness, porosity and microhardness of the as sprayed coatings have also been reported. The blending resulted into the formation of composite-like coatings where, the Cr3C2 phase was nearly uniformly distributed into the NiCrFeSiBC matrix. The results have been discussed with respect to the existing literature.