Long-Term Strength Estimation of Zirconia Ceramics

Abstract

A standard experimental assessment of the service life of high-temperature zirconia ceramics (GOST 4070–2014) requires the use of complicated heating and measuring equipment and hundreds of expensive specimens. This necessitates the development of calculation methods for evaluating long-term strength depending on the thermomechanical loading conditions without carrying out a full range of laboratory tests. The existing experimental estimation models of the primary and secondary creep regimes of ceramics consider the temperature range up to 1600°C, which is lower than zirconia limiting operating temperatures (2000°C and higher). Based on the Norton – Bailey law, long-term strength estimation of fully stabilized zirconia ceramics is carried out. Using previously known experimental data of other authors for ceramics made of fully stabilized zirconia (0.1Y2O3 + 0.9ZrO2), the creep constants values were calculated at high-temperature (1600–1800 °C) loading levels ≤5 MPa. A power-law regression equation with a high degree of correlation that evaluates the creep of the test material under loads up to 20 MPa and temperatures up to 2100 °C is proposed.