GOALI: Understanding the Microstructural Evolution and High-Temperature Behavior of Osmium-Ruthenium Coatings for Dispenser Cathodes

这一奖项的研究目标是在分配阴极的制造和使用过程中更好地了解Os-Ru涂层。这些阴极在行波管和阴极射线管等器件中用作电子源，必须经受住包括真空、高工作温度和高电流密度在内的苛刻环境条件。Os-Ru膜在加工和初期使用过程中经历了显著的微结构变化，但必须保持完好以保持阴极的电子发射。具有重要科学意义的课题包括薄膜微结构对难熔金属扩散的影响，以及薄膜织构对电子功函数的影响。还有几个与工业相关的问题，包括如何实现更高的排放、更长的寿命和/或更低的工作温度。通过系统地研究微结构对退火态和调质后阴极成分稳定性和发射性能的影响，将建立一个科学的、基于微结构的对Os-Ru薄膜涂层的理解。该项目所获得的知识将有助于将分配阴极行业从一个有几十年经验的经验领域，发展到一个具有科学认识和为提高性能量身定制新涂层的能力的领域。该项目将为阴极制造的根本性转变建立所需的知识，并减轻材料成本上升的影响。如果成功实施，这项研究的结果将导致改进的设备分配阴极行业。这将降低生产成本和提高产量，并将通过延长阴极寿命和可靠性而使客户受益。该项目将通过提供对工业产生直接和切实影响的研究经验，以及通过为PI教授的顶石设计课程提供与工业相关的材料问题，来促进研究生和本科教育。

The research objective of this award is an improved understanding of osmium-ruthenium coatings during their fabrication and service in dispenser cathodes. These cathodes, which serve as electron sources in devices such as traveling wave tubes and cathode ray tubes, must withstand demanding environmental conditions including vacuum, high operational temperature and high current density. The osmium-ruthenium films undergo significant microstructural changes during processing and initial service, but must remain intact to maintain electron emission from the cathode. Topics of fundamental scientific importance include the effects of thin film microstructure on the diffusion of refractory metals, as well as the effects of film texture on electron work function. There are also several industrially relevant issues, including how to achieve enhanced emission, longer lifetime and/or lower operating temperature. By systematically investigating the effects of microstructure on the compositional stability and emission properties of annealed and conditioned cathodes, a scientific, microstructure-based understanding of osmium-ruthenium film coatings will be built.The knowledge gained from this project will help advance the dispenser cathode industry from an empirical field with decades of experience, to a field with scientific understanding and the ability to tailor new coatings for improved performance. This project will establish the knowledge needed for a fundamental shift in cathode manufacturing and also mitigate the effects of increasing material costs. If successfully implemented, the results of this research will lead to improved devices for the dispenser cathode industry. This will enable lowered production costs and improved yield, and will benefit customers by increasing cathode lifetime and reliability. The project will enhance both graduate and undergraduate education by providing research experience that has a direct and tangible impact on industry and by providing industrially relevant materials problems for the capstone design course taught by the PI.