Burning Characteristics of Ammonium Nitrate‐based Composite Propellants Supplemented with MnO₂

Abstract

Abstract Ammonium nitrate (AN)‐based composite propellants have several major problems, namely, a low burning rate, poor ignitability, low energy, and high hygroscopicity. The addition of a burning catalyst proved to be effective in improving the burning characteristics of AN‐based propellants. In this study, the burning characteristics of AN‐based propellants supplemented with MnO 2 as a burning catalyst were investigated. The addition of MnO 2 is known to improve the ignitability at low pressure. The most effective amount of MnO 2 added ( ξ ) for increasing the burning rate is found to be 4 %. The increasing ratio with ξ is virtually independent of the burning pressure and the AN content. However, the pressure exponent unfortunately increased by addition of MnO 2 . The apparent activation energy of the thermal decomposition for AN and the propellant is decreased by addition of MnO 2 . From thermal decomposition kinetics it was found that MnO 2 could accelerate the thermal decomposition reaction of AN in the condensed phase, and therefore, the burning characteristics of the AN‐based propellant are improved.