Influence of Y2O3 Contents on the Y-Gd-Hf-O Directly-Heated Pressed Cathode Thermionic Emission Properties [Y2O3 含量对 Y-Gd-Hf-O 直热式压制阴极发射性能的影响]

作者：Wang X.; Wang X.; Luo J.; Li Y.

来源：Rare Metal Materials and Engineering, 2022, 51(12): 4658-4665.

• anti-electron bombardment
• lifetime
• thermionic emission
• work function
• Y2O3 doped

To improve the Y-Gd-Hf-O pressed cathode thermionic emission ability, Sc2O3 doped Y-Gd-Hf-O pressed cathodes with different molar ratios of Y2O3/HfO2 were prepared. The results show that the cathode with ratio of 5/2 demonstrates the best emission ability of 2.79 A/cm2 at 1500 ℃. The cathode works stably over 1320 h at 1500 ℃ with the load of 1 A/cm2 during the lifetime test, and the emission current decreases to 86% of the initial one after 10 W for 696 h continuous bombardment at the same temperature, reflecting a good anti-electron bombardment ability. XPS depth profile results show that the main active substances in work are concentrated in the depth range of 50 nm from the surface. After cathode being activated, the SEM and EDS results show that the active materials diameter increases to an extent, and the surface n-type semiconductor contents increase with the increase of Y2O3 content, which is favorable for enhancing the conductivity, improving thermionic emission, and lowering the work function.

• 单位
  中国科学院大学