阴极基体材料对空间行波管阴极寿命的影响  

Influence of Substrate on Cathode Lifetime for Space Traveling Wave Tubes

作　　者：夏扬[1] 谢元锋[1] 姜珩[1] 吕宏[1] XIA Yang;XIE Yuan-feng;JIANG Heng;LV Hong(General Research Institute of Non-ferrous Metals, Beijing 100088, China)

机构地区：[1]北京有色金属研究总院,北京100088

出　　处：《真空电子技术》2017年第3期42-46,共5页Vacuum Electronics

摘　　要：本文结合空间行波管阴极失效机制,从阴极基体材料研究进展入手分析阴极寿命的影响因素。阴极基体的粉末颗粒性能、多孔基体孔径性能等对活性物质蒸发率有影响。寿命过程中,阴极表面功函数因表面膜层合金化程度、基体表面钡覆盖率和基体内钡供应通道条件变化等因素会发生持续改变。分析结果认为,选择形状规则(球形最佳)、平均粒径4μm左右的窄粒度分布粉末为原料,有利于优化基体孔隙性能和降低闭孔率。采用WIr、WOs等混合基合金阴极或混合基底表面覆Os、Ir等贵金属膜,可有效延缓阴极表面合金化速度,可降低蒸发并保持低逸出功,有效改善阴极寿命。According to the failure mechanism of the cathode used in space travelling wave tubes,the developments of cathode material were illustrated and factors limiting the long-lifetime of cathodes were analyzed.Effects of particle characteristics and porous performance of the substrate on evaporation rate of active material penetrating into the substrate were discussed.The work function of M-cathode would change continuously in working process because of the influence of elemental alloying on surface,barium supplying in channels and surface coverage.It was suggested that narrow size distributed powders with regular shapes and mean grain size of 4μm were helpful for improving porous property and reducing percentage of close pores.Mixing cathode substrate with noble metal Os or Ir,or covering cathode surface with Os or Ir film,could effectively slow down the alloying speed,reduce the evaporation,keep low work function,and so improve cathodes lifetime.

关 键 词：阴极基体#功函数 合金化 月极寿命 

分 类 号：TN105[电子电信—物理电子学]