折叠波导行波管铪栅极退火温度及其性能(英文)

Annealing temperature and property of Hf used for FWG-TWT

在充分考虑电子枪栅极的工作环境后,对铪(Hf)栅极进行了800、900和1000℃的真空退火处理,对其组织、织构特点进行了分析,并利用离子束辅助沉积技术在Ba-W阴极表面分别沉积金属钼膜和铪膜,以模拟栅控行波管中钼栅极和铪栅极表面吸附阴极蒸发物质时的表面状态,测试了这两种栅极表面"热电子发射"能力和"二次电子发射"系数。结果表明,随着退火温度的升高,铪(Hf)栅极的结晶度、晶粒尺寸增加,织构减少,铪的最佳退火温度为900℃,铪栅极表面吸附的阴极发射物质要远少于钼栅极,用金属铪作栅极材料能有效抑制栅电子发射。

After fully considering working environment of electron gun grid cathode,Hf-grids were annealed at 800 ℃,900 ℃,1000 ℃ in vacuum. Microstructure and texture of the Hf-grids were studied by means of SEM,MRD and Schulz technology. In order to compare the property of Mo with Hf,Mo and Hf were respectively deposited onto the surface of the cathode by ion beam assisted deposition for imitating the surface conditions of Mo-grids and Hf-grids,the cathode was fabricated by Ba-W materials. The capability of restraining electron emission was evaluated by measuring the ratios of thermo-electronic emission and secondary electron emission coefficient on testing system.The results show that crystallinity and grain size increase and fiber structure decreases with increasing annealing temperature. The optimality temperature is 900 ℃. It is found that Hf can effectively restrain the electron emission.