Specific physicochemical behavior of trace "hot" atoms during phase transitions in metals. I. Behavior of trace indium atoms in metallic tin

The behavior of trace In-113m atoms formed in the nuclear reaction in metalic tin [Sn-112(n,gamma)Sn-113 --> In-113m] was studied by the method of the radioactive equilibrium shift, absorption Mossbauer spectroscopy, Mossbauer spectroscopy on conversion electrons, and X-ray diffraction analysis. Certain anomalies (such as accelerated transport of trace atoms to the metal surface and their transfer into the gas phase) were found in the diffusion behavior of radioactive atoms in the bulk and surface layers of metalic tin and in their physicochemical behavior at the metal-gas boundary during phase transitions (e.g., melting, alpha --> beta and beta --> gamma polymorphic transitions, and thermal rearrangement of the surface). The dependence of these processes on the type of the phase transition was studied.