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本文提出了解释镧-碳化钨(La-WC)阴极发射大和抗油蒸汽中毒能力强的一些设想,并通过实验,验证了所提出的设想。在La-WC阴极的工作温度范围内,La和 WC发生化学反应,生成La_2C_3。La_2C_3也是一种良好的发射材料,它具有与镧相近的逸出功。La_2C_3能与镧形成共熔体,对钨基底浸润良好,易形成较好的发射层,而使发射显著增大。La-WC阴极抗油蒸汽中毒是由于污染的碳与共熔体中的镧形成La_2C_3,而La_2C_3也是良好的发射物质的缘故。
In this paper, some ideas to explain the capability of lanthanum-tungsten carbide (La-WC) cathode to emit large and resistant to steam poisoning are presented. The proposed concept is validated through experiments. In the operating temperature range of La-WC cathode, La and WC chemically react to form La 2 C 3. La 2 C 3 is also a good emitting material, which has a work function similar to that of lanthanum. La 2 C 3 can form a eutectic with lanthanum and infiltrate well into the tungsten substrate to form a better emissive layer with a significant increase in emission. La-WC cathodic anti-steam poisoning is due to the formation of La 2 C 3 from contaminated carbon and lanthanum in the eutectic, and La 2 C 3 is also a good emitting material.