M型阴极离子斑扫描电镜分析

SEM Analysis of Ion-Bombardment Nicks of M-Type Dispenser Cathodes

采用扫描电镜及X射线能谱仪对覆膜阴极的离子斑进行了分析。分析表明,阴极离子斑中心部分的贵金属覆膜(Os膜)已被完全溅射掉;离子斑周边覆膜仍保留一部分,但Ba和O的含量极低。进一步分析表明,离子轰击不仅使离子斑区域贵金属膜受损,同时使该区域Ba-O键的含量大幅度降低,从而导致该区域及整个阴极的发射出现明显下降。

The ion-bombardment nicks of M-type dispenser cathodes have been analyzed with scan electron microscope and X ray energy spectrum. The results indicate that the noble metal film （Os film） in the centre of the ion-bombardment nicks had been completely sputtered off already, and a part of the film surrounding the ion-bombardment nick was still remained, with an extremely lower content of Ba and O. Analyses further indicate that the ion bombardment not only makes the regional noble metal film damaged, but also makes the content of this regional Ba-O bond reduce by a large margin at the same time, thus lead to the fact that the obvious decline has appeared in the emission of this area and the whole cathode.