Oxygen Tracer Diffusion in Single‐Crystal Alumina

Oxygen tracer diffusion coefficients are determined in single‐crystal alumina samples; with differing dopant levels using the gas‐exchange technique. The diffusion direction is parallel to the c ‐axis and the ambient P o 2 is 1 atm (10 5 Pa) for all experiments except a single run with a low P o 2 The diffusion is insensitive to both; impurities and ambient P o 2 The insensitivities are discussed in terms of point‐defect clustering. Prior tracer studies are compared and discussed.