Journal of Materials Science

, Volume 36, Issue 15, pp 3737–3744

Hydrothermal degradation mechanism of tetragonal Zirconia

Article

DOI: 10.1023/A:1017925800904

Cite this article as:
Guo, X. Journal of Materials Science (2001) 36: 3737. doi:10.1023/A:1017925800904

Abstract

The hydrothermal degradation mechanism of tetragonal ZrO2previously proposed by the author was elaborated. In this mechanism, the annihilation of oxygen vacancies is a crucial step, and the grain boundaries play an important role in propagating the degradation. The degradation process of a 3 mol% Y2O3doped ZrO2pellet annealed in water vapor was monitored via impedance spectroscopy, the bulk and the grain boundary resistivity, and the grain boundary thickness were all found to increase with increasing annealing time, proving the annihilation of oxygen vacancies in the bulk and especially at the grain boundaries. The fracture surfaces of the annealed pellet were studied by SEM, only intergranular cracks were observed, indicating the propagation of the degradation along the grain boundaries. The mechanism predicts that the electrode resistance should increase when the electrodes are exposed to water vapor. Silver electrodes on a 8 mol% Y2O3doped ZrO2pellet were annealed in the mixture of oxygen and water vapor, the electrode resistance was found to increase with increasing annealing time. The prediction was thus proven.

Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  • Xin Guo
    • 1
  1. 1.State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan, Hubei Province 430070, People's Republic of China; Department of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan, Hubei ProvincePeople's Republic of China