Three Possible Ways to Inhibit the Ammonium Perchlorate Combustion Process

Abstract

Proceeding from the assumption that the ammonium perchlorate (AP) combustion process is controlled by dissociation into ammonia and perchloric acid, three possible ways of decelerating the deflagration are considered: a) adding the substances readily generating in decomposition of the ammonia in order to shift the equilibrium of the dissociation to the left; b) adding the substances which can bind the perchloric acid or products of its decomposition into less reactive compounds than perchloric acid itself or original AP; and c) adding the substances which can inhibit the decomposition of perchloric acid. In all cases, the burning rate must decrease in consequence of the reduction in the oxidation rate of ammonia. The readily decomposed salts of ammonia, halogenides of the metals, deoxidants, and hexachlorethane were studied as additives. Experiments were made up in a constant pressure bomb in nitrogenous atmosphere over pressure range from lower pressure limit to 1000 atm. It was shown that the addition of 1% of the salts of ammonia or the halogenides of lead or cadmium to AP, for example, reduces Rm by a factor of 3-4 at low pressures. Deoxidants and inhibitors of the HCIO4 decomposition are less effective as burning inhibitors. The synergistic effect in deflagration of AP with inhibitors of different types is also studied in the work. It was shown that intensification of the inhibiting effect of the additives takes place when the double additives of ammonium salts and halogenides of metals are added to AP. The addition of the salts of ammonia and deoxidants to AP does not entail the intensification of the inhibiting effect. An explanation of the regularity obtained and the mechanism of synergistic effect is given in the paper. I. Introduction