Low-power microwave-discharge forms in hydrocarbon atmosphere

Different forms of the steady-state microwave discharges in argon-methane mixture at atmospheric pressure find great interest in exploring both nature phenomena and finding wide-technology applications, like coating, welding, plasma-induced chemical catalysis, or as a plasmatron for the ignitions of flames in different applications. Atmospheric microwave discharges are attractive in that they demand no pumping systems and are easy to access, explore, and manipulate. A 7-GHz generator (15-150 W) coupled with microwave coaxial plasma burner was used for plasma production in argon/methane flow (1-10 L/min). The possibility of synthesizing carbon materials by carbon vapor deposition in conditions of such discharge was demonstrated. Growing of the 5-cm-long carbon filament was observed with the speed of up to 1 cm/min. Pictures of plasma forms and synthesized samples are presented. Index Terms--Atmospheric pressure microwave discharge, carbon condensation, carbon synthesis, methane plasma, microwave discharge.