碳化硅-石墨复合阴极的可控制备及原位碳化硅改善强流发射特性的机理研究

高功率微波的实用化进程迫切需要开发束流密度大、发射阈值低、等离子体膨胀速度慢且寿命长的新型阴极。项目基于石墨阴极中引入碳化硅可显著提高电子发射性能和微波脉冲宽度的发现，围绕碳化硅-石墨复合阴极的制备和强流发射特性开展相关研究。项目将借助工艺调控和微观分析手段，采用气相渗透法原位制备多种形态（颗粒/纳米线及其尺寸/取向/分布等）的碳化硅-石墨复合阴极，阐明碳化硅的原位生长机制并解决其在石墨阴极坯体上的可控生长问题；通过对阴极材料物理特性、微观状态、电子发射特性的分析，阐明碳化硅材料自身的特性与强流发射性能的内在联系，明确碳化硅在强流发射中的作用，揭示碳化硅显著提高强流发射性能和微波产生特性的内在机制；通过考察不同重复频率下的运行情况，评估复合阴极的寿命并明确碳化硅对复合阴极束流品质及重频运行特性的影响。项目的实施将为基于碳化硅的强流阴极在高功率微波等领域的应用提供理论支撑。

The practical process of high power microwave urgently needs to develop new cathodes with high current density, low emission threshold, slow plasma expansion velocity and long lifetime. Based on a new idea that the introduction of SiC in graphite cathode can significantly improve electron emission performance and microwave pulse width, the project will study the preparation and intense electron emission properties of SiC-graphite cathode. Firstly, the SiC-based cathodes with various forms (particles/nanowires and their size/orientation/distribution, etc.) will be developed by Chemical Vapor Infiltration (CVI), and the in-situ growth mechanism of SiC will be elucidated and its controllable growth problems on the graphite surface will be solved with the help of processes control and microscopic analysis method. Secondly, the physical properties, microstructures and electron emission characteristics of the cathode materials will be analyzed to clarify the intrinsic relationship between the properties of the SiC material and the intense electron emission characteristics, and the role of the SiC in the intense electron emission and the inherent mechanism of determining the emission characteristics of the SiC-based cathodes. Thirdly, by testing the operation of the cathode at different repetition frequencies, the lifetime of the cathode will be evaluated, and the effect of the SiC on the quality of electron beam as well as the operating characteristics at repetitively frequencies of the SiC-based cathode will be clarified. The implementation of the project will provide theoretical guidance for the application of SiC-based cathodes in high power microwave and other fields.