Thermal decomposition kinetics of potassium iodate Part II. Effect of gamma-irradiation on the rate and kinetics of decomposition

摘要

The effect of gamma ray irradiation on the rate and kinetics of thermal decomposition of potassium iodate (KIO_3) has been studied by thermogravimetry (TG) under non-isothermal conditions at different heating rates (3, 5, 7, and 10 K min~(-1)). The thermal decomposition data were analyzed using isoconversional methods of Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose, and Friedman. Irradiation with gamma rays increases the rate of the decomposition and is dependent on the irradiation dose. The activation energy decreases on irradiation. The enhancement of the rate of the thermal decomposition of KIO_3 upon irradiation is due to the combined effect of the production of displacements and extended lattice defects and chemical damage in KIO_3. Non-isothermal model fitting method of analysis showed that the thermal decomposition of irradiated KIO_3 is best described by the contracting sphere model equation, with an activation energy value of ~340 kJ mol~(-1).