无机溶胶凝胶法制备铝酸盐对钡钨阴极性能的影响研究

针对高性能、长寿命空间行波管对阴极性能的苛刻需求,本文采用一种新型无机溶胶凝胶法制备钡钨阴极用铝酸盐,利用扫描电镜、X射线衍射仪分析铝酸盐的微观形貌、物相结构,并研究不同工艺路径制备铝酸盐对阴极发射性能、蒸发性能、寿命的影响。相比固相法制备的铝酸盐及阴极,无机溶胶凝胶法制备的铝酸盐烧结温度低、结晶性好、颗粒尺寸小(约1μm)且均匀性分散;无机溶胶凝胶法制备的阴极发射得到提高,发射拐点电流密度约为32.91 A/cm2,发射斜率约为1.403(1050℃(光亮温度));阴极蒸发速率较低,为2.5×10^(-10) g/cm^(2)·s(1050℃),同时阴极寿命提高了1.43倍。

Effect of Aluminate Prepared by Inorganic Sol-Gel Method on Emission Properties of Tungsten Dispenser Cathodes

In order to meet the demanding requirements of high-performance and long-life space traveling wave tubes for cathodes, a new inorganic sol-gel method is adopted to prepare aluminates for tungsten dispenser cathodes. The microscopic morphology and physical structure of the aluminates are analyzed by SEM and XRD, respectively. The effects of different process routes on the cathode emission performance, evaporation performance and working lifetime are investigated. Compared with the aluminates and cathodes prepared by solid phase method, the aluminates prepared by inorganic sol-gel method have lower sintering temperature, better crystallinity, smaller particle size(~1 μm) and more uniform distribution;the emission performance and emission uniformity of the cathodes prepared by inorganic sol-gel method are improved with an emission inflection current density of 32.91 A/cm2 and an emission slope of 1.403(1050℃);the evaporation rate of the cathode is as low as 2.5×10^-10 g/cm²·s, and the cathode lifetime is increased by a factor of 1.43.