Jaj. Rodrigues et al., NITRIDE AND CARBIDE OF MOLYBDENUM AND TUNGSTEN AS SUBSTITUTES OF IRIDIUM FOR THE CATALYSTS USED FOR SPACE-COMMUNICATION, Catalysis letters, 45(1-2), 1997, pp. 1-3
Satellites are equipped with microthrusters that control their orbit a
nd attitude. The thrust is achieved by the catalytic decomposition of
hydrazine by iridium supported on alumina. As nitrides and carbides of
molybdenum and tungsten behave like noble metals in many catalytic re
actions, they were tried in a 2 newton hydrazine microthruster. Their
performance was similar to that of the iridium catalyst, with respect
to ignition delay and thrust. Their mechanical resistance appears high
er than that of iridium-based catalyst. This application is the first
practical one for nitrides and carbides of early transition metals as
substitutes of noble metals, a possibility first reported in 1973.