Silicon as high performance fuel additive for ammonium nitrate

Abstract

The addition of silicon (Si) powder from about 0.40 to 6.00 weight percent o ammonium nitrate (AN) propellant formulations as a fuel source results in a substantial increase in performance specific impulse (Isp). Theoretical Isp of AN propellant can be enhanced to levels approaching conventional in-service propellant formulations containing much more hazardous ingredients. Using inert or energetic polymer binders, AN propellant formulations are possible that will meet the performance requirements of most tactical missile systems when silicon is used as a fuel additive. Silicon powder when used to replace elemental carbon in most formulations has two major advantages: (1) an increase in theoretical Isp and (2) an improved propellant combustion efficiency by increasing propellant burning temperature. An improvement in propellant burning properties are also expected. The adjustment of weight percent ammonium nitrate in the AN propellant formulation is made as the silicon powder is adjusted over the range of 0.40 weight percent to 6.00 to achieve the preferred results. Formulations are mixed, cast and cured by techniques and methods that are commonly used in the industry and that are known by personnel skilled in the art of propellant formulating.