Atmospheric plasma sprayed coatings of nanostructured zirconia

Nanostructured zirconia coating has been fabricated by atmospheric plasma spraying. The microstructure of the coating has been characterized with SEM and XRD, and the microhardness has been measured. The results show ZrO2 coating possessed two kinds of structure. One was the poorly consolidatedly structure, which was composed of nanosized particles. The other was an overlapping structure, which consisted of micrometer size particles. The former was the main structure in the coating. The zirconia coating had the same phase composition as the starting powder and the thickness of coating was quite heterogeneous. The as-sprayed nano zirconia coating had a similar microhardness to sintered ZrO2, which was much higher than the conventional couterpart.