Correlation between deposition efficiency, hardness and elastic modulus for thermally sprayed zirconia

Results concerning the relationship between deposition efficiency and mechanical properties with coating roughness are presented. A commercial partially stabilized zirconia powder was plasma sprayed at different power levels, H2/Ar ratio and spray distance. Coatings sprayed at high deposition efficiencies demonstrated improved mechanical properties. The deposition efficiency is also proportional to the coating roughness. When prepared with a high plasma power and a high H2/Ar ratio, and at short spray distances, these coatings exhibited the highest deposition efficiency and coating roughness. The high coating roughness associated with a high deposition efficiency arises because coarse powder particles are likely to be melted at higher plasma power. However, opposite trends were also observed within different regimes of powder size distribution and torch power. Another objective of this work was to demonstrate that a surface profilometer can be used to understand the deposition efficiency and mechanical properties of thermal spray coatings