The effective diffusion coefficient, De, during sintering or diffusional creep of a polycrystalline ionic (ceramic) compound, MaXb, was re-examined and was suggested to be given by De = DMDX/(bDM + aDX), where Di was the diffusion coefficient of ion i (= M, X), in agreement with some previous investigations. This expression should be applicable to any system where ambipolar diffusion was driven by a stress gradient.

Ambipolar Diffusion in Sintering and Diffusional Creep of Ionic Compounds. S.J.L.Kang, H.I.Yoo: Journal of the American Ceramic Society, 2004, 87[12], 2286