THE INVESTIGATION ON NON-REDUCTION CHARACTERISTICS OF THERMAL ION EMISSION OF GRAPHITE--A comparison for characteristics of thermal ion emission of different graphite

The non-reduction characteristics of thermal ion emission for six kinds of graphite with different source, purity and crystal structure and one high pure carbon powder were studied in this paper.the results show that the efficacy of thermal ion emission of graphite is weakly relative to purity and size of graphite, while decided by crystal structure of graphite. The graphite with perfect crystal structure has high efficacy of thermal ion emission.