The Use of Amorphous Carbon Electrodes in High Voltage A.C. Arc Excitation

Abstract

Amorphous carbon electrodes offer certain advantages over graphite electrodes for spectrochemical analyses. They burn more evenly, and are poorer conductors of heat and current than graphite electrodes. However, their abrasiveness and brittleness in handling make them much less convenient to machine than graphite electrodes. Mellichamp and Finnegan (1) have shown that an enhancement of spectral lines occurred when a carbon crater was substituted for a graphite crater in d.c. arc excitation, and that the time for complete burning of the sample was considerably reduced with carbon craters. They noted that arc wandering decreased with carbon counter electrodes, and reported that intensity ratios were virtually the same for graphite and carbon counter electrodes.