Optimization of Grit Blasting Conditions by Supersonic Air Spraying

This work assesses the feasibility of using a high-velocity airfuel (HVAF) gun both to grit blast and spray substrate surfaces. A design of experiments (DoE) approach was used to establish relationships between grit blasting variables, substrate surface conditions, and coating properties. Alumina was selected as the abrasive media, the substrates were HSLA steel, and CrC-NiCr and Fe-based powders were used to form the coatings. Uncoated and as-sprayed substrates were characterized based on hardness, residue levels, surface roughness profiles, and adhesion strength, which are correlated with mesh size, feed rate, offset angle, and standoff distance.