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The valence of element yttrium of Y 2O 3 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 Y 2O 3 cathode was discussed. It was proved that reaction between powder Y 2O 3 and Mo 2C can happen at 1 173 K, and Y 2O 3 be reduced to metallic yttrium. After the powder mixture of Y 2O 3 and Mo 2C is heat treated at 1 873 K, 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. [
The valence of element yttrium of Y 2O 3 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 Y 2O 3 cathode was discussed. It was verified that reaction Between powder Y 2O 3 and Mo 2C can happen at 1 173 K, and Y 2O 3 be reduced to metallic yttrium. After the powder mixture of Y 2O 3 and Mo 2C is heat treated at 1 873 K, 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 one of yttrium at the surface does not provide emission current, but the momoatomic active surface layer has a lower work function than clean molybdenum. [