Formulation effects on the burning rate of aluminized solid propellants

Abstract

Porous ammonium perchlorate was prepared by a fluidization process at 230°C, the product of which was used as a partial substitute for crystalline ammonium perchlorate in composite solid propellants. Fourteen aluminized propellants were divided into five groups containing various promoters (modifiers) having different burning rates in order to compare the effects of aluminum powder particle size on the burning rates of the propellants. Aluminum powders having three particle sizes (6-9,16-19, and 60 /im) were used. The burning rate was measured in a strand burner at 30, 50, 70, 100, and 150 atm of nitrogen pressure. The burning rates of propellants containing catocene or n-butylferrocene as a promoter increased with decreasing aluminum particle size. When copper chromite and/or ferric oxide was used as a promoter, the particle size of aluminum had no effect on the burning rate of the propellant. Therefore, the effect of aluminum particle size on the burning rate depends on the burning rate modifier in the propellant.