The influence of implanted yttrium on the mechanism of growth of Cr/sub 2/O/sub 3/ on Cr

One of the apparent effects of Y on the growth of Cr/sub 2/O/sub 3/ scales, based on inert marker studies, is a change in growth mechanism from predominant cation diffusion to predominant anion diffusion. The interpretation of inert marker studies has always been open to question, and a recent study of the mechanisms of growth of α-Al/sub 2/O/sub 3/ scales using /sup 18/O tracer techniques has demonstrated that the results of inert marker studies can be misleading. Results of /sup 18/O tracer oxidation experiments conducted with Y-implanted and Y-free Cr are reported in this paper, which demonstrate that Y implantation does change the mechanism of oxide growth