Wear Behavior of Thermally-Sprayed ZrO_2 Coatings after Treatment with Spark Plasma Sintering (SPS)

摘要

A magnesia stabilized zirconia (ZrO2-25wt% MgO) ceramic coating was deposited on the SS 400 substrate by flame spraying. The thermal spray coated steel then exposed to the treatment using spark plasma sintering (SPS) which is a new process for the densification of porous material. In the SPS process, the ceramic-coated steel was heated rapidly under vacuum and compressive loading at the temperatures of 900 and 950 °C for 10 min. The effect of SPS treatment on the wear behavior of zirconia ceramic coatings was studied. The result showed that the as-sprayed coating had a large amount of porosity up to 22% and after treatment with SPS, the porosity fell to below 5%. The bond strength and microhardness of the coating were also increased. The result from erosion wear test at different impingement angles showed that the coating after SPS treatment exhibited lower cumulative weight loss. The erosion wear mechanism on coatings was the subsurface cracks, which propagated almost parallel to the blasted surface, resulting in plough of coating material. Also the coatings after SPS treatment exhibited lower cumulative weight loss after sliding wear test compared with the as-sprayed coatings. The smeared powdery ceramic debris is revealed both on as-sprayed and SPS-treated coatings.