原位材料置换的离子光学系统在非平衡多物理场条件下的寿命加速因子获取方法研究

The ion optics, also known as grid assemble, is the core assemble of the ion thruster. It is shown that the life and reliability of the ion optics determine the life of the ion thruster. As the most efficient new type of electric thruster, ion thruster is an inevitable choice for deep space exploration mission in China, which will be applied to the main propulsion system of spacecraft to execute orbital transfer mission. In order to obtain its working life data, the duration assessment under real working condition with a single thruster is adopted generally, which not only spends a long process of duration assessment and a huge cost, but also has uncertainty with a single thruster. This project intends to carry out experimental research on sputtering etching of the ion optics within a real working condition by in-situ material replacement methodology. It is proposed to use gold or oxygen-free copper to replace multiple positions of the ion optics, whose substrate is the sputtering resistant molybdenum, to improve sputtering yield, accelerate structural failure. The reliability of ion optics with in-situ material replacement will be evaluated by using the reliability analysis methodology of accelerated life. Combined with theoretical calculation, analyze the evolution mechanism of sputtering characteristics with different materials within a non-equilibrium multi-physics field, obtain the rules of life acceleration of ion optics, identify acceleration factor, and condense life acceleration factor experiment universal methodology of the ion optics. On this account, it opens up a new and efficient technical way for the life assessment and reliability verification of ion thrusters.

离子光学系统也称栅极组件，是离子推力器的核心部组件，其寿命和可靠性直接决定着离子推力器的寿命。离子推力器作为当今最为高效的新型电推力器，将其应用于航天器轨道转移任务的主推进系统是我国深空探测任务的必然选择，为取得其工作寿命数据，通常采取真实工况下单台全周期寿命考核，这项试验考核周期长，耗资大,且单台考核带有一定的不确定性。本项目拟通过离子光学系统原位材料置换法，在真实工况下开展离子光学系统溅射刻蚀试验研究，拟利用金或无氧铜多处原位置换基材为耐溅射金属钼的离子光学系统，提高溅射产额，加快结构失效，并通过加速寿命可靠性分析方法评估置换后的离子光学系统的可靠性。结合理论计算，分析非平衡多物理场条件下不同材料溅射特性的演化机制，获取离子光学系统的寿命加速规律，确定加速因子，凝练离子光学系统寿命加速因子试验通用方法，以此为离子推力器地面寿命考核及可靠性验证开辟更为高效的技术途径。

本项目通过离子光学系统Cu材料置换法，在真实工况下开展带有Cu制加速件的离子光学系统溅射刻蚀研究。首先，在Cu制加速件上还原栅片同等大小的栅极小孔，在高真空环境下开展摸底试验，获取带有Cu制加速件的离子光学系统的电子返流的失效判据，同时开展了带有Cu制加速件的离子光学系统的离子透明度研究。在加速寿命试验过程中，对试验环境可能造成的影响进行了研究。本项目试验与理论相结合，获取了加速因子为2.95，且加速因子随功率变化成线性关系。同时，为了优化置换工艺，初步开展了热态栅间距的研究，以此为离子推力器地面寿命考核及可靠性验证开辟更为高效的技术途径。