Sliding Wear Behavior of Plasma Sprayed Zirconia Ceramic Coating Under Different Conditions

The sliding wear behavior of ZrO₂-22wt%MgO (MZ) and ZrO₂-8wt%Y₂O₃ (YZ) deposited on a cast aluminum alloy with bond layer (NiCrCoAlY) by plasma spray against a SiC ball was investigated under dry and lubrication conditions at room temperature. At all load conditions, the wear mechanisms of the MZ and YZ coatings were almost the same. The wear mechanism involved material transfer and pullout under dry condition, but micro-fractures and spallation under lubrication condition. When oil was used for lubrication, the friction coefficient of the sliding pairs and the wear loss of the ceramics were reduced. The wear loss of the MZ coating was less than that of the YZ coating under dry test, but more than that of the YZ coating under lubrication test. The test conditions and the mechanical properties of the ceramic coatings were correlated to the wear performance.