On the Oxidation and Combustion of AlH3 a Potential Fuel for Rocket Propellants and Gas Generators

摘要

Aluminum hydride is a promising candidate for application in energetic materials and hydrogen storages.E.g.an AP/HTPB rocket propellant filled with alane was calculated for a 100 N s kg-1 higher specific impulse compared to the same concentration of aluminum.Different investigations on alpha-A1H3 polyhedra using thermoanalytical methods and X-ray diffraction were performed to receive a better understanding of dehydration at about 450 K,passivation of the remaining porous aluminum particles and further oxidation.A modeling approach to describe these conversions including diffusion processes,Avrami-Erofeev mechanism and Arrhenius type reaction steps of n-th order were introduced.Results were discussed in comparison to experimental investigations under pressure with model propellants on the base of gelled pure nitromethane and also filled with alane or pure aluminum in concentrations of 5%,10% and 15%.Both alane and aluminum increase the burning rate on a factor of two correlated with a temperature increase up to 500 K and more.A mesa burning effect at 6 to 10 MPa was indicated by the mixtures with alane.