Mossbauer investigations of grain-boundary diffusion and segregation

Possibilities of grain-boundary diffusion and segregation studies using nuclear gamma-resonance spectroscopy (NGR) are considered. It is shown that the results of the Mossbauer investigations testify the necessity to specify the classical Fisher's model of grain-boundary diffusion, and a possible way of such specification is suggested. It is demonstrated that investigation of, grain boundaries using emission Mossbauer spectroscopy appreciably supplement the information obtained from the diffusion profiles analysis. In particular, Mossbauer investigations make it possible to evaluate directly the grain-boundary segregation factor, to determine the grain-boundary diffusion mechanism, to estimate the rate of the diffusant pumping from a grain boundary core into the bulk, etc.