一种新型氧化物阴极致密涂层性能研究  

Study on the Dense Coating Property of a New Oxide Cathode

作　　者：张敏[1] 高玉娟[1] 柯森林 ZHANG Min;GAO Yu-juan;KE Sen-lin(The 12th Research Institute of China Electronics Technology Group Corporation,Beijing 100015,P. R. China)

机构地区：[1]中国电子科技集团公司第十二研究所,北京100015

出　　处：《真空电子技术》2017年第6期45-49,共5页Vacuum Electronics

基　　金：军委装备发展部科研订购局预研领域基金(批准号:6140862010106)资助的课题

摘　　要：涂层作为氧化物阴极的重要组成部分,对其发射性能具有重要影响。采用大气等离子喷涂技术制备的致密结实涂层有效解决了传统涂覆方法引起的涂层容易脱落和活性物质蒸发大的问题,有效地提高了阴极发射性能。为了进一步研究等离子喷涂氧化物阴极涂层性能,本文从蒸发性能、抗中毒性能、导热性三个方面对涂层性能进行研究,发现涂层的致密程度对活性物质蒸发、抗中毒性能、导热性都具有重要影响。致密涂层有利于减少钡原子的蒸发,但同时不利于钡原子的扩散,可能因为钡原子不能及时得到补充而引起阴极中毒,因此等离子喷涂氧化物阴极老炼时间比传统喷涂氧化物阴极的老炼时间长。致密涂层有利于提高阴极的导热性,从而有利于支取大密度电流。Carbonates coating,as an important component of oxide cathode,has a great influence on the emission performance of the cathode.The oxide cathode coating usually painted or sprayed onto the nickelbase material at room temperature after having mixed with a nitrocellulose binder to provide adhesion to the nickel surface has weak adhesion strength to the metal base and low heat conductivity,which makes the coating vulnerable to overheating and even peeling off,and undermine the emission performance of the cathode.Plasma-sprayed oxide cathode was prepared in the previous experiment by employing air plasma spraying technique,which made a dense and strong coating,and improved the pulsed current emission density dramatically.In order to further explore the coating property,the coating property of plasma-sprayed oxide cathode with regard to evaporation,resistance against poisoning,and thermal conductivity is investigated by testing and comparing the evaporation of plasma-sprayed oxide cathode and conventionally coated oxide cathode in a dynamic evaporation test system.The experiment of resistance against poisoning is made by comparing the direct current values under different temperatures and voltages of a plasma-sprayed oxide cathode aged for 10 hours and 25 hours in a water-cooled anode vacuum system.The experimental results show that the dense coating is helpful to reduce the evaporation of Ba atoms,and at the same time detrimental to the diffusion of Ba atom,making the cathode vulnerable to poisoning resulted from failure to supplement enough Ba atoms.Therefore,it takes longer time to age plasma-sprayed oxide cathode than conventionally coated oxide cathode.The thermal conductivity experiment is made by watching temperature change of plasma-sprayed oxide cathode and conventionally coated oxide cathode in the water-cooled anode dynamic vacuum system with the increase of voltage,indicating that plasma-sprayed oxide cathode has stronger resistance against overheating than that of conventionally coated oxide cathode and h

关 键 词：等离子喷涂 氧化物阴极 蒸发 导热性 

分 类 号：TN103[电子电信—物理电子学]