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Thecompression creep behavior ofY,O,-stabilized ZrO, (YSZ) was studied at temperatures to 2000°C. The function of Y 2 0 3 content and grain size was tested in specimens with various impurity concentrations and porosity distributions. For relatively fine-grained specimens, creep rates increased with the 1.5 power of the applied stress at low stresses and with the third power at high stresses. The results for coarse-grained specimens can, in general, be fit by the cube dependence. The 1.5 power can be reduced to a linear dependence by correcting for an apparent threshold stress, which decreases with increasing temperature. Creep activation energies for YSZ are 128k 10 kcal/mol, independent of Y z 0 3 content, impurity level, grain size, and porosity distribution. In addition, over a broad range of temperatures and stresses the absolute values of the steadystate creep rates are influenced only by grain size and 0, partial pressure.

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