HVOF Coatings in Improving Resistance to Surface Degradation

The HVOF coatings have high hardness, low oxidation, high abrasion resistance,high erosion-corrosion resistance, high wear resistance, low porosity, high density, superior bond strength, thick coating, fine finishing capability and lower oxide content. Particle heating is more uniform and efficient due to the high turbulence experienced by the particles within the combustion chamber. Further the particles have much shorter exposure time in flight due to high particle velocities. The present study is an attempt to evaluate the elevated temperature corrosion behaviour of HVOF sprayed Cr3C2-NiCr, Ni-20Cr, WC-Co and Stellite-6 coatings by the accelerated testing at an elevated temperature of 900 deg C with salt mixture of Na¬2SO4-60%V2O5, reported to be most aggressive environment under cyclic conditions.