Environmental degradation of CuO-doped Y-TZP ceramics

The phase stabilities of plain and CuO-doped (up to 0.2 wt.%) coated 2.5 mol% Y-TZP ceramics, sintered at 1300°C, were investigated by exposure in hostile environments for periods of up to 2000 h. CuO additions significantly reduced the rate of tetragonal to monoclinic phase transformation compared with that for undoped samples. In addition the mechanical properties of the doped materials were better in all cases. Specimen sectioning, however, revealed that after 200 h even the samples with CuO had developed thin, measurable monoclinic layers. Doping of Y-TZP ceramics with small amounts of CuO is one method of reducing ageing degradation without sacrificing other properties.