A REVIEW OF HVOF COATED STEELS FOR HYDRO TURBINE APPLICATIONS
Keywords:HVOF, hardness, slurry erosion, scratch resistance, thermal coatings.
In this review, the slurry erosion behaviour of various HVOF coated steels for hydro turbine applications has been addressed. The specific surface characteristics can be imparted to substrate material by selection of suitable coating materials. Hard coating particles such as B4C and NiCr can be incorporated in structure of composite coatings to obtain refined structure with increased hardness, adhesion and erosion resistance. The various process parameters such as impingement angle, impact velocity and sand discharge have remarkable effect on slurry erosion characteristics of composite coated substrates. HVOF is a promising methodology due to capability of fabrication of hard thermal coatings with high scratch resistance, excellent wear and superior slurry erosion resistance and other advantages associated with the procedure.