Effect of substrate temperature on the properties of coatings and splats deposited by wire arc spraying

Abstract

Experiments were conducted to study the effect of impact velocity and substrate temperature on the properties of individual splats and coatings deposited with a wire arc spraying system. Aluminum was sprayed onto polished AISI304L coupons maintained at temperatures ranging from 25 °C to 450 °C. In-flight particle parameters (diameter, velocity, temperature) were measured using a DPV2000 system. Individual splats deposited on the substrate were photographed. At low substrate temperature droplets splashed, forming irregular splats; at higher temperatures there was no splashing and splats formed circular disks. The temperature at which the transition occurred decreased with increasing impact velocity. Raising substrate temperature increased both deposition efficiency and adhesion strength. Predictions from analytical models to calculate splat diameter and transition temperature were compared with experimental measurements and found to agree well.