The diffusivity of O in high-purity polycrystalline material was determined, by using 18O as a tracer, in specimens which had been prepared by annealing powder at 1400C. The diffusion process was monitored by means of reaction gas analysis or by using micro-balance methods. It was found that, at temperatures ranging from 800 to 1100C, the O tracer diffusion coefficient (table 3) could be described by:

D (cm2/s) = 5.24 x 107 exp[-491(kJ/mol)/RT]

These values were smaller than published data, and this difference was suggested to be due to the lack of an O concentration gradient in the present study.

Y.Ikuma, T.Murakami: Journal of the Electrochemical Society, 1996, 143[8], 2698-705

Table 3

Diffusivity of 18O in In2O3