[Investigation of tin and chromium grain boundary diffusion in iron by microautoradiography]

Microautoradiography using conversion electron and Auger electron of the isotopes 119mSn and 51Cr which were diffused from the surface in pure iron was investigated. The surface layers were removed successively by chemical reagents to prepare the specimen for microautoradiographs. The density of silver particles was measured in the boundary region and was normalized by comparing with the density near the triple point of the grain boundary. Differences of the diffusion coefficients in the grain boundary were investigated from the frequency diagram of the isotope concentrations near the boundary in individual specimens.