Mechanical properties and wear behaviors of Cu-doped zirconia-toughened alumina ceramics

Cu-doped, ZrO2-toughened alumina (ZTA) ceramics with varying amounts of Cu (0, 1.5, 3.0, and 5.0 wt%), denoted as Cu/ZTA, were prepared using a fast hot pressing sintering furnace. The microstructure, mechanical properties, tribological properties, and wear mechanism of Cu/ZTA ceramics were subsequently studied. The results showed that Cu doping can cause the formation of holes in the ZTA ceramics. The formation of holes originated from the O2 produced by CuO decomposition at high temperatures and the phase transformation of ZrO2. Cu/ZTA ceramics with 5.0 wt% Cu exhibited significantly improved toughness and tribological properties but diminished hardness. The worn surface analysis of the Cu/ZTA ceramics revealed that their wear mechanism primarily involved abrasive wear and material transfer. The ZrO2 and Cu particles were first pulled out from the wear track to form wear debris during friction. The 5.0 wt% Cu/ZTA ceramic exhibited decreased hardness and high toughness, which made it easier for the abrasive debris to adhere to the surface and holes. Additionally, the wear debris was crushed into the holes formed by Cu doping. The results indicated that a reduction in the number of wear particles at the friction interface could impede the wear of the abrasive particles. Overall, the Cu/ZTA ceramic with 5.0 wt% Cu was found to be a promising structure material with excellent tribological properties.