Low-temperature degradation behaviour of microwave sintered CuO-doped Y-TZP ceramics

The low-temperature degradation (LTD) behaviour of undoped and 0.2 % copper oxide-doped 3 mol% yttria-tetragonal zirconia polycrystal (Y-TZP) via microwave (MWV) sintering were studied in this work. The MWV-sintered samples were heated at temperatures varying from 1100 to 1400 degrees C, with a heating rate of 30 degrees C per min and holding time of 5 min. These samples were then assessed and compared with the conventional (CV) sintered samples that were executed at the ramp rate of 10 degrees C per min. The MWV and CV-sintered Y-TZPs were aged in an autoclave vessel and kept in an oven at 180 degrees C/10 bar up at different intervals, up to 200 h. The results show no substantial difference in the microstructure or grain size between MWV and CV-sintered samples at above 1250 degrees C. In addition, there was no monoclinic phase detected from the X-ray diffraction (XRD) for both undoped and doped Y-TZPs after ageing for 200 h, regardless of sintering methods, with sintering temperature up to 1400 degrees C. It was revealed that Y-TZPs with a grain size smaller than 0.28 lm were resistant to hydrothermal ageing. The study also indicated that the beneficial effect of microwave diminished when samples were sintered at elevated temperatures. Copyright (c) 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the 14th AUN/SEED-Net Regional Conference on Materials and 4th International Postgraduate Conference on Materials, Minerals and Polymer (RCM & MAMIP 2021).

Automated summary

The low-temperature degradation behavior of undoped and copper oxide-doped yttria-tetragonal zirconia polycrystal (Y-TZP) samples via microwave sintering was studied. The results showed that there was no significant difference in microstructure or grain size between microwave and conventional sintered samples at temperatures above 1250°C. Monoclinic phase was not detected after 200 hours of hydrothermal aging, regardless of sintering methods or temperature. It was also observed that the beneficial effect of microwave diminished at elevated temperatures.