Influence of Spray Process Parameters in Cascaded Plasma Spray Gun on YSZ Coating Morphology and Properties

Oerlikon Metco’s SinplexPro cascaded plasma gun is known to improve coating deposition efficiency and stabilize coating quality. However, few studies about influences of process parameters on coating properties by SinplexPro can be found. In this study, YSZ coated coupons were made by SinplexPro with various process parameters. During spray processes, particle temperatures and velocities were measured. Furthermore, SEM observations of coating surface as well as cross-section and abrasion test were conducted on coated coupons to study coating properties. As a result, with the optimized low temperature and high velocity (LT-HV) coating condition, it was found that not only deposition efficiency was high but also abrasion resistance was increased. In contrast, with high temperature and low velocity (HT-LV) coating condition, deposition efficiency was increased, but coating porosities were higher and abrasion resistance were lower compared to LT-HV coating condition. Furthermore, formations of shell-shaped splats were found on the coating surface made with HT-LV coating condition. It is considered that these shell-shaped splats and coating morphology contributed to abrasion resistance of the coating. In this study, correlations between coating morphology as well as properties and spray process parameters were reported.