Kinetics of Hydrazine Decomposition on Iridium and Alumina Supported Iridium Catalysts.

摘要

The kinetics of heterogeneous hydrazine decomposition were determined over the temperature range of 460to 700K for a polycrystalline iridium surface,and the temperature range of 350to 450K for an alumina supported iridium catalyst. A change in reaction mechanism and/or number of active catalytic sites was observed at approximately 450K for each catalyst. This is attributed to the irreversible,dissociative adsorption of hydrazine on a significant number of catalytic sites below 450K. Catalyst attrition mechanisms in monopropellant hydrazine engines are discussed in the light of this kinetic behavior. Recommendations are made concerning further elucidation of basic processes taking place in monopropellant engine cold starts. (Author)