Burning Characteristics of Ammonium Nitrate‐Based Composite Propellants Supplemented with Fe 2 O 3

Ammonium 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 Fe 2 O 3 as a burning catalyst were investigated. The addition of Fe 2 O 3 is known to improve the ignitability at low pressure. Fe 2 O 3 addition also increases the burning rate, while the pressure exponent generally decreases. The increasing ratio ( R ) of the burning rate of the AN/Fe 2 O 3 propellant to that of the corresponding AN propellant vs. the amount of Fe 2 O 3 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, Fe 2 O 3 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.