Splat and coating formation of wire arc sprayed aluminum

To study the effect of impact velocity and substrate temperature have on splat morphology, aluminum wire was sprayed, using the ValuArc 100 wire arc spray gun, onto polished AISI304L coupons held at various temperatures. In-flight particle parameters (size, velocity, temperature) were measured using a DPV 2000 system. Individual splats deposited on the substrate were photographed. Comparisons between the in-flight particle size distribution and the final splat size distribution showed that increasing substrate temperature results in increased mean spread factor. A transition temperature from splash to disk splats was determined. Experiments also showed that increasing substrate temperature was found to improve both deposition efficiency and adhesion strength. Coatings were also produced at various substrate temperatures and porosity levels measured. Analysis of the coating microstructure showed that increasing the substrate temperature helps to reduce voids at the substrate/coating interface. Porosity levels were measured to be less than 5% in all cases.