Radiation-chemical decomposition of heavy metal azides—III. The role of two-valence impurity cations in radiation-stimulated processes in silver azide

Abstract

Ion and electron transfer in the irradiation field as well as silver azide radiolysis doped with Cu 2+, Pb 2+, Cd 2+ cations topography and kinetics have been studied. A certain part of impurity cations appeared to enter the crystal lattice to form solid solutions, they being chemisorbed partially on the surface to form complexes with low mobility. Ion transfer parameters change greatly due to interstitial silver ions concentration decrease, cation vacancy concentration increase and because of doped cations participating in the transfer in doped systems. Impurity cations being electron traps and recommendation centers influence the radiation conductivity value. In addition, Cu 2+ ions lose their mobility caused by their transition into the atomic state. In fact, during silver azide radiation-chemical decomposition bivalent impurity cations become radiolytic metal particle formation centers. This has been inferred from the fact that the radiolytic metal contains as much as 30% of dopants at the initial stages, which has experimentally been proved. This results in kinetic curve change and general radiolysis acceleration at the initial stage with decomposition proceeding under nonstationary conditions. The impurity cation effect seemed insignificant for larger degrees of radiolysis with decomposition proceeding under stationary conditions. The scheme of silver azide radiolysis with no radiolytic particle metal participating in the growth process during thermo-activated stages has been proposed, accounting for the results obtained.