Solid state chemistry of copper chromite used as a catalyst for the burning of ammonium perchlorate/polystyrene propellants

Abstract

The formation of copper chromite by solid-state reaction between basic copper carbonate and chromium carbonate has been investigated. It has been established that the extent of reaction is 98% even when the reactants are heated for 15 min at 800°C. The burning rate of polystyrene/ammonium perchlorate propellants containing mixtures of basic copper carbonate and chromium carbonate as additives was measured after prior heating at 800°C for different times. The catalytic action depends on the formation of fine grains of copper chromite. Although this is favored by high temperature, higher temperatures and longer duration of prior heating are unfavorable factors since these promote greater sintering. Experimental results show that optimization is obtained when copper chromite is prepared by heating a mixture of the carbonates in the weight ratio 1:2.37 at 800°C for 2 hr.