Abstract
Ultrafine carbide powders of Fe-Si-C and WC1-x were prepared utilizing a new radiofrequency thermal plasma system and their chemical properties were examined.
Ultrafine Fe-Si-C powders were prepared in the plasma from the reactant gases of SiH4-CH4-Fe(CO)5. Phases of powders were classified to two groups; one is composed of β-FeSi2, which was very active for the selective formation of olefin in the Fischer-Tropsch reaction, the other is of α-Fe, Fe3Si and Fe5Si3, which gave high CO conversion. Ultrafine WC1-x powder in the phase of 90-95 wt% with the particle diameter of 5-20nm was obtained from the reactant gases in the mole ratio of CH4/WO3 with over than 15. It was stable thermally below 1, 000°C under Ar atmosphere but it began to decompose to W2C over 1, 000°C. Ultrafine WC1-x powder promoted catalytically the formation of n-butane in the hydrogenation of cis-2-butene.
