覆膜阴极表面处理工艺对性能的影响  

The Impact of Coating Cathode Surface Treatment Process on Performance

作　　者：王卉[1] 张珂[1] 韩良 WANG Hui;ZHANG Ke;HAN Liang(Beijing Institute of Vacuum Electronics Technology,Beijing 100015,China)

机构地区：[1]北京真空电子技术研究所,北京100015

出　　处：《中国钨业》2024年第3期81-88,共8页China Tungsten Industry

摘　　要：真空电子器件的日益发展对阴极电子源提出了大电流密度、高发射均匀性、低蒸散速率和长寿命等更高的要求。为了研究阴极表面形貌变化对阴极性能的影响,本试验采用不同的表面处理工艺在M型阴极发射面形成不同的微观形貌,并在相同条件下进行预处理和测试。阴极表面处理后的微观形貌分析结果表明:对比机械处理,喷砂处理后钨基表面产生了均匀细小的凹凸面,有效地增加了电子发射表面积,提高了发射活性物质Ba分布的均匀性;喷砂处理后阴极表面粗糙度增加了两倍,这有利于提高钨基与金属膜层的结合力,延长阴极寿命。通过发射和蒸发特性的比较,发现喷砂处理阴极的脉冲发射能力和均匀性均优于机械处理阴极;喷砂处理阴极的蒸发速率大于机械处理阴极,但老炼一段时间以后,两种阴极的蒸发速率均有所下降。The rapid advancement of vacuum electronic devices has necessitated enhanced performance requirements for cathode electron sources,including high current density,superior emission uniformity,minimal evapotranspiration rates,and prolonged lifespan.This paper investigates the impact of varying cathode surface morphologies on cathode performance through the application of different surface treatment processes,which yield distinct microstructures on the M-type cathode emission surfaces.All pre-treatments and tests were conducted under controlled conditions.Microstructural analysis reveals that,compared to mechanical treatments,sandblasting produces a uniform and finely textured concave-convex surface on the tungsten-based cathode,significantly expanding the effective electron emission area and enhancing the uniform distribution of the emission-active material,barium(Ba).Consequently,the surface roughness of sandblasted cathodes doubles,which is advantageous for improving the adhesion strength between the tungsten base and metal film layers,thereby extending the cathode's lifespan.Emission and evaporation characteristics analysis indicates that sandblasted cathodes exhibit superior pulse emission capabilities and uniformity compared to their mechanically treated counterparts.Although the evaporation rate of the sandblasted cathodes is greater than that of the mechanically treated ones,both cathode types exhibit a decline in evaporation rates after a period of aging.

关 键 词：M型阴极 表面处理工艺 喷砂处理 均匀性 发射性能 蒸发速率 

分 类 号：TG175.3[金属学及工艺—金属表面处理] TG146.4[金属学及工艺—金属学]