Effect of anion doping on the thermal decomposition of potassium bromate

Structural defects were introduced into the potassium bromate (PB) lattice in the form of SO42- and Cl- ions in the process of crystal growth. It was assumed that these doped crystals PB(Cl-) and PB(SO42-) are composed of a t wo phase system, one being the perfect PB lattice and the other distorted r egions due to induced defects. Isothermal decomposition of doped and normal PB samples was carried out gasometrically between the temperature range 65 3-663 K. The alpha -t plots reveal that the process occurs through initial gas evolution, acceleratory and decay stages. It also confirmed that doping enhances the rate of the reaction, the effect being more pronounced in the case of PB(SO42-). The data are found to be well fitted to the Prout-Tompk ins and Avrami-Erofe'ev mechanisms.