Burning Characteristics of Ammonium Nitrate‐Based Composite Propellants Supplemented with Fe2O3

Abstract

AbstractAmmonium nitrate (AN)‐based composite propellants have attracted a considerable amount of attention because of the clean burning nature of AN as an oxidizer. However, such propellants have several disadvantages such as poor ignition and a low burning rate. In this study, the burning characteristics of AN‐based propellants supplemented with Fe2O3 as a burning catalyst were investigated. The addition of Fe2O3 is known to improve the ignitability at low pressure. Fe2O3 addition also increases the burning rate, while the pressure exponent generally decreases. The increasing ratio (R) of the burning rate of the AN/Fe2O3 propellant to that of the corresponding AN propellant vs. the amount of Fe2O3 added (ξ) depends on the burning pressure and AN content. R decreases at threshold value of ξ. The most effective value of ξ for increasing the burning rate was found to be 4 % for the propellant at 80 % AN, and the value generally decreased with decreasing AN content. According to thermal decomposition kinetics, Fe2O3 accelerates the reactions of AN and binder decomposition gases in the condensed‐ and/or gas‐phase reaction zones. The burning characteristics of the AN‐based propellant were improved by combining catalysts with differing catalytic mechanisms instead of supplementing the propellant with a single catalyst owing to the multiplicative effect of the former.