ISOTHERMAL STUDIES ON GAMMA-IRRADIATED OXALATES OF YTTRIUM AND SAMARIUM

The influence of gamma-irradiation (0.01-1.0 MGy) on the isothermal de composition of Y-2(C2O4)(3) and Sm-2(C2O4)(3) has been studied by gas evolution method between the temperature range 603-643 and 623-663 K r espectively. The ''alpha-t'' plots of both unirradiated and irradiated salts follow: (i) initial gas evolution, (ii) a short acceleratory pe riod, and (iii) a long decay period. The data on all categories of sam ples are discussed in the light of various kinetic models for solid st ate reactions and are found to be well-fitted to Prout-Tompkins and Av rami-Erofeyev mechanisms. Results on unirradiated and irradiated, Y-2( C2O4)(3) are also well explained by contracting square relationship. T he fractional decomposition, alpha is enhanced by irradiation, the eff ect being higher at higher doses in case of both the substances. Irrad iation has marginal effect on the energy of activation of the accelera tory and decay periods in the case of Sm-2(C2O4)(3) but it reduces the same in the former stage and reverse phenomenon occurs in the latter period in the case of Y-2(C2O4)(3). Copyright (C) 1997 Elsevier Scienc e Ltd.