Investigation on Thermionic Emission Characteristics of Pressed Sc2O3 Doped Y-Gd-Hf-O Directly-heated Cathode
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摘要: 为了提高Y-Gd-Hf-O阴极耐电子轰击能力，该文通过高能球磨、压制和高温氢气烧结，制备了一种Sc2O3掺杂Y-Gd-Hf-O压制式直热式阴极。该阴极在1550 °C工作温度下，经过10 W电子连续轰击480 h后，发射电流密度下降至初始值的87.5%，表现出良好的耐电子轰击能力。阴极表面的微观形貌、成分组成分析表明，经压制后氢气气氛烧结，阴极表面呈陶瓷状结构形态，有利于提高阴极的耐电子轰击能力；经高温烧结、激活后表面形成了n型半导体Y2O3-x层，对改善阴极表面导电性、降低逸出功和提高热发射有促进作用。Abstract: To improve the Y-Gd-Hf-O cathodes anti-electron bombardment ability, a scandia doped cathode is prepared by a pressing technique combined with sintering in hydrogen atmosphere. The tested result shows that the emitting current from the cathode operating at 1550 °C can remain to 87.5% of the initial one after continuous electron bombardment of 10 W for 480 h, reflecting a better anti-electron bombardment capability. The surface microstructure analysis result indicates that a cermet structure has been formed. A n-type semiconductor Y2O3-x layer has generated on the cathode surface after being sintered and activated at high temperature, which is favorable for enhancing the thermionic emission, improving the surface conductivity, and lowering the work function.
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Key words:
- Cathode thermionic emission /
- Magnetron /
- Work function /
- Anti-bombing
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表 1 阴极氢炉烧结前后EDS原子含量(%)
元素 烧结前 烧结后 区域A 区域B 区域A 区域B Y 24.08 24.39 23.23 23.99 Gd 3.22 2.94 2.96 2.95 Hf 14.51 14.46 14.80 15.38 Sc 5.08 5.07 5.44 5.36 O 53.11 53.13 53.57 52.32 
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