ABSTRACT
High-velocity oxy-fuel (HVOF) method of thermal spray coating has found extensive application in recent years in many industries. Its attractive features have been extraordinary quality, high flexibility, ease of working with and cost-effectiveness. In this chapter, effects of Cr3C2-25NiCr coating produced by HVOF spray on the performance, in particular, the hot corrosion resistance, of nickel-based superalloys at different temperatures has been reviewed. Further, important attributes of the coatings – thickness, porosity, microstructure and mechanical behaviour are extensively addressed. In addition, the work done by some of the present authors on the effect of HVOF coating Cr3C2-25NiCr on the hot corrosion behaviour of alloy 80A has been discussed. The hot corrosion behaviour and the beneficial effect of the coating have been explained in terms of the chemical reactions taking place at high temperatures.
