Effect of counterbody on the dry sliding wear performance of plasma sprayed calcia-stabilized zirconia coating

In this study, the effect of counterbody on the dry sliding wear behavior of plasma sprayed calcia-stabilized zirconia coating was investigated. The commercial ZrO2-5CaO coating powder (Metco 201NS, -53 + 11 mu m) was deposited onto the surface of AISI 316L substrate using Atmospheric Plasma Spray method. Dry sliding wear tests were performed with Al2O3 and WC-Co counterbody balls at different loads (5 N, 10 N and 15 N) and sliding speeds (10 mm/s, 20 mm/s and 30 mm/s) using a ball-on-disc device. From the test results, the COF values obtained from the Al2O3 ball were recorded to be lower than that of the WC-Co ball especially at 20 N and 30 N loads. The sliding speed did not cause a remarkable change in the COF values of the wear tests performed with both counterbody balls. However, in the case of WC-Co ball, COF values also increased especially with increasing the load from 5 N to 10 N at the 20 mm/s of sliding speed. In general, increasing load and sliding speed led to an increase in the wear volume loss values for all the tests. When using Al2O3 ball, under the 5 N load, lots of pitting and spalling zones were observed, whereas for 10 N and 15 N loads, plastically deformed worn areas which had lots of wear debris and deep cracks were determined. As for the WC-Co ball, the plastic deformation was observed as the predominant wear mechanism as well as the swelling-induced spallation and delamination. In addition, the wear mechanisms identified as a result of this study were explained by associating them with the Hertzian contact theory.