It was noted that experimentally measured grain size compensated diffusion creep rates were essentially identical for cubic, tetragonal and monoclinic zirconia. This suggested a similarity of the absolute magnitudes of their grain boundary diffusion coefficients. However, grain growth was substantially slower in tetragonal zirconia; due to significant grain boundary segregation.

Diffusion, Diffusion Creep and Grain Growth Characteristics of Nanocrystalline and Fine-Grained Monoclinic, Tetragonal and Cubic Zirconia. A.H.Chokshi: Scripta Materialia, 2003, 48[6], 791-6