Influence of γ-irradiation and Dy2O3 on the decomposition of barium oxalate: A thermogravimetric study

Effect of γ-irradiation (4.0 MGy ) and the presence of Dy2O3 (10 mol% ) on the decomposition of anhydrous barium oxalate has been investigated by the rising temperature technique. It is evident from the data that in all the materials, decomposition occurs through (i) a slow reaction stage and (ii) a fast stage followed by a decay period. The loss of ‘CO’ from the oxalate is governed by a two-dimensional phase boundary reaction with cylindrical geometry, the power law of the reaction order, 0.5, in the irradiated salt and three-dimensional nuclei growth in case of mixture. The data were well explained by the contracting area (R2) model indicating that irradiation as well as mixing enhanced the rate of reaction and decreased the energy of activation, the effect being more prominent in the latter case.