Low-temperature degradation and defect relationship in yttria-tetragonal zirconia polycrystal ceramic

Abstract

In this work, the relationship between tetragonal to monoclinic phase transformation and photoluminescence spectrum were studied for 3 mol% yttria-tetragonal zirconia polycrystal samples sintered in air and argon atmosphere at 1500 degrees C. A low-temperature degradation study was conducted under autoclave conditions containing superheated steam at 180 degrees C and 10 bar vapour pressure for periods up to 12 hours. Photoluminescence studies were conducted using a photoluminescence spectroscope with helium-cadmium laser at a wavelength of 325 nm as the excitation source, and the phase content in the zirconia samples was measured using X-ray diffractometer. The studies concluded that argon gas sintered samples have higher structural vacancy than air sintered samples; the argon gas sintered sample showed a more rapid phase transformation than the air sintered sample and also showed that the defect associated with oxygen vacancies in the zirconia lattice increases with increasing aging time