Emission mechanism of Mo-Y₂O₃ cathode

来源期刊：中国有色金属学报(英文版)2000年第5期

论文作者：王金淑 周美玲 聂祚仁 张久兴 罗丰华 左铁镛

文章页码：576 - 579

Key words：emission mechanism; Mo-Y₂O₃ cathode; valence; yttrium

Abstract: The valence of element yttrium of Y₂O₃-Mo cathode material was studied by thermal analysis, X-ray diffraction analysis, scanning electron microscopy and X-ray photoelectron spectra, and the emission mechanism of Mo-Y₂O₃ cathode was discussed. It was proved that reaction between powder Y₂O₃and Mo₂C can happen at 1173K, and Y₂O₃ be reduced to metallic yttrium. After the powder mixture of Y₂O₃and Mo₂C is heat treated at 1873K, yttrium exists in two kinds of state—yttrium of zero valence and yttrium of three valences. The formation of monoatomic layer of metallic yttrium at the surface of filament is the cause of emissivity of the cathode. Yttrium at the surface doesn’t provide emission current, but the momoatomic active surface layer has a lower work function than clean molybdenum.