Thermal Decomposition of Barium Azide

Abstract

THE rate of decomposition of solids is a function of the rates of: (1) nuclear formation; (2) propagation of the reaction outwards from the nuclei. Both these components might be expected to be influenced by external stimuli. The formation of nuclei by bombardment of the solid with α- or β-particles, or by irradiation with ultraviolet light, X-rays and γ-rays should be possible in favourable circumstances, and by the same agencies the rate of propagation of the reaction might be accelerated. For example, the effects of pre-irradiation by high-energy γ-rays (∼ 1 MeV) on the subsequent thermal decomposition of the permanganates of sodium, potassium, rubidium, cæsium and silver are to shorten the induction period and accelerate the reaction¹. It was of interest, therefore, to examine the effect of pre-irradiation by γ-rays on the isothermal decomposition of barium azide. There have been several previous investigations of the effects of radiation on barium azide. Pre-irradiation with α-particles², X-rays³, and ultra-violet light⁴ accelerates the rate of subsequent thermal decomposition, but to our knowledge no study has been made of the effect of γ-rays.