PREPARATION AND PROPERTIES OF HVOF COATED B4C +NiCr STEEL FOR HYDRO TURBINE APPLICATIONS
Keywords:hardness, adhesion, erosion resistance, composite coating, HVOF
Higher micro hardness, adhesion and erosion resistance of materials used for hydro turbine applications is required to achieve a longer service life of equipments. In this paper, B4C +NiCr composite coatings were prepared on 18Cr8Ni stainless steel with HVOF process to improve hardness, adhesion strength and erosion resistance of coated substrate. The effect of process parameters impingement angle, impact velocity impingement angle and sand discharge on slurry erosion characteristics of composite coated substrate was investigated. The microstructure of coating was analyzed by using scanning electron microscope and energy dispersive spectroscopy. The incorporation of hard B4C and NiCr particles results in refined structure and increased hardness, adhesion and erosion resistance.