Despite all the work conducted over many decades, there remains a major problem in understanding diffusion in alumina. It is certain that all measurements of diffusion in alumina refer to extrinsic diffusion. However, the experimental activation energy is larger than any theoretical production by a factor of 2. The problem with grain boundary diffusion is, if anything, worse. The most complete set of experimental data suggests that the activation energy for boundary diffusion is 50% larger than for bulk diffusion. This article looks at the problems involved in understanding the experimental data and in producing theoretical models and propose a strategy for resolving the problems.
Origin
University College London
Journal Title
J Am Ceram Soc 86 4 2003 554-559
Sector
Special Glass
Class
S 2504