Burning rate catalysts for composite solid propellants

Abstract

The combustion of composite solid propellants was studied using ammonium dichromate, chromium carbonate, chromium oxide, basic copper carbonate and cupric oxide as additives. Burning rates were considerably enhanced in each case. Flame temperatures were measured and found to be higher than in cases where additives were not used. Carbonates were more effective than the corresponding oxides. TGA studies showed that the rate of decomposition of AP as well as the rates of polymer and propellant degradation were all enhanced by the catalysts. The mechanism of catalytic action was also investigated. TGA studies and other experiments showed that in the case of the carbonate, the main species catalysing the burning rate was the oxide which could act as a catalyst in the flame or on the propellant surface. It has been suggested that enhanced flame temperature is due to accelerated reactions in the gas phase. Analysis shows that an increase in the burning rate occurs primarily as a result of catalytic reactions in the gas phase or gaseous reactions on the surface, and is not due to exothermic condensed phase reactions.