MHz猝发式多脉冲下微纳改性环氧树脂复合材料的真空沿面闪络特性研究

The vacuum surface flashover is a major factor in the vacuum insulation systems, and becomes an important and difficult problem restricting the development of particle accelerators and other large pulsed power devices. As research of multiple pulse flash X-ray photography is carried out at home and abroad, the multiple pulsed vacuum surface flashover becomes more prominent, but few relevant researches have been published. Therefore, this study intends to prepare epoxy composite specimens filled with nano- and micro-filler by using epoxy, Al2O3•3H2O and TiO2 inorganic fillers, as well as other additives. And then the vacuum surface flashover performance of the specimens under single nanosecond pulse and MHz repetition rate pulse will be compared. At the same time, this paper intends to improve the surface conductivity, surface charge decay, secondary electron emission coefficient, trap distribution parameters through the epoxy composites formulation design and thus to improve the vacuum surface flashover voltage of the epoxy composites under MHz repetition rate pulse.

真空沿面闪络是真空绝缘系统中绝缘失效的主要原因，也是制约粒子加速器等大型脉冲功率装置发展的重点难点问题。随着国内外开展多脉冲X射线多幅闪光照相的研究，多脉冲下的真空沿面闪络问题更加突出，而这方面的研究相对较少。因此，本项目拟以环氧树脂为基体，选择微米级和纳米级的Al2O3•3H2O和TiO2等无机填料，辅以其他助剂，制备出微纳改性环氧树脂复合材料试验样品，对比研究试样在单纳秒脉冲和MHz猝发式多纳秒脉冲下的真空沿面闪络特性。通过微米级与纳米级填料共混调节复合材料的表面电导率、表面电荷衰减、二次电子发射系数和陷阱分布等参数，来提高MHz猝发式多脉冲下环氧树脂复合材料的真空沿面闪络电压。

本项目以微纳改性环氧树脂复合材料配方设计及制备工艺为基础，对复合材料的介电性能和表面电性能进行调控。研究了填料对环氧树脂表面电导率、表面电荷的衰减特性、表面耐电弧性能等的影响机制。研究了纳秒脉冲下不同填料比环氧树脂复合材料的真空沿面闪络特性。然后，采用电场仿真计算了介电常数和表面电荷对真空绝缘环电场分布的影响。得出以下结论：当填料比大于80phr时，ATH/环氧树脂复合材料的表面耐电弧能力明显优于纯环氧树脂，沿面闪络电压和纯环氧树脂相当，表面电导率比纯环氧树脂高一个数量级，表面电荷衰减时间缩短30%。本项目的研究结果为开展全尺寸部件的实验研究提供了基础，为强流直线感应加速器等大型脉冲功率装置用真空绝缘环的研制提供了有效途径。