GENERATION OF MICROWAVE PLASMA UNDER HIGH-PRESSURE AND FABRICATION OFULTRAFINE CARBON PARTICLES

A microwave plasma generator, which functions under high pressure, has been developed and used in the fabrication of fine carbon particles. The plasma generator is a two-stage-type resonator, which consists of rectangular and semi-cylindrical-type resonators which are coupled in series for torching plasma and keeping it stable under high pressure. The plasma can be torched in helium gas at 3 x 10(6) Pa by tuning the dimensions of apparatus elements. Fine carbon particles of similar to 50 nm are obtained using a mixture of helium and methane gas. The part icles are found to be crystalline from the results of transparent elec tron microscopy and diffraction analysis.