Decomposition of Hydrazine by Tungsten Oxycarbides: The Influence of Macroporosity and Mechanical Strength on a 2 N Microthruster Engine

Abstract

The aim of this work was to prepare tungsten oxycarbides by Temperature Programmed Reaction (TPR), starting with previously molded macroporous tungsten oxide (WO3). The tungsten oxycarbides were prepared by one of two different methods: direct carburization with CH4/H2 to obtain WC or preliminary formation of nitrides with NH3 to obtain W2N, followed by carburization to W2C and WC with CH4/H2. Results suggested that the carburization of the W2N was incomplete, resulting in an oxycarbonitride, or did not occur at all, with the end material being W2N. From among the materials prepared, two catalysts were selected as a function of their mechanical properties, and their performances were compared with a 2 N microthruster using the Shell 405 commercial catalyst in the reaction of hydrazine decomposition

Catalytic Decomposition of Energetic Compounds: Gas Generators and Propulsion1A list of abbreviations/acronyms used in the text is provided at the end of the chpater

“…A key point of these investigations was the importance of bimodal porosity displaying micropores for catalytic activity (high surface area), and macropores to provide an outward part for the hot gases formed in the core of the particles. Tungsten oxycarbide [115] and niobium oxynitride [116] have also been investigated for their activities. Recently, both molybdenum carbide [111] and nitride [112,113], supported on γ -alumina, were investigated by the group of T. Zhang in China; molybdenum nitride with a high Mo loading (23 wt.% Mo, 1.5 monolayer) produced a good performance in a 10-N thruster.…”