基于纳米复合介质层的氧化铝陶瓷表面电荷时空演变行为及其沿面闪络特性研究

Surface flashover on the interface between insulator and vacuum severely restricts the performance of high-voltage electronics and equipment, and impedes their further improvement on size. Al2O3 ceramic is a common insulating material that has been widely employed. However, the improvement on its surface flashover performance via mechanical method costs too much, while many of surface modification methods could not make obvious enhancement due to the high mechanical strength and complicated surface. This work will firstly construct nanocomposite layer with adjustable surface electrical properties, which comprise of metal oxides layer on gradient metal-implanted-layer by employing plasma immersion ion implantation and deposition technical. The mesh-assisted mean and dynamic behavior of plasma sheath expansion will be studied. Secondly, space-time evolvement process relating surface charge accumulation and dissipation behavior on nanocomposite layers will be researched. The generating and developing process of surface flashover would be studied by direct optical observation via ultra-fast framing system and multiple photoelectricity measurement. The flashover developing theory will be developed and improved based on the study of surface charge space-time evolvement process, which would be helpful for the enhancement of Al2O3 ceramic insulting performance.

绝缘介质的真空沿面闪络现象已成为制约高压器件和装置性能的关键因素之一，并成为其小型化的瓶颈所在。氧化铝陶瓷作为常用绝缘材料，目前通过机械手段改善其闪络性能成本较高，而其较高的机械强度和复杂的表面特性也限制了多数表面改性方法的应用。本项目拟利用金属离子注入与沉积技术，基于高效金属栅网辅助和等离子体鞘层扩展行为研究，在氧化铝陶瓷表面构筑注金属氧化物纳米复合介质层，实现氧化铝陶瓷表面电学特性规律调控。在此基础上，分别研究具有不同电学特性表面的电荷积累与消散行为，建立表面电荷时空演化动力学模型。通过高速分幅相机，辅以多种光电探测手段，连续观测沿面闪络发展过程中的发光现象，建立基于表面电荷时空演化行为的沿面闪络发展机理和模型，有效提升氧化铝陶瓷材料的高场强下沿面闪络性能。

绝缘介质的真空沿面闪络现象已成为制约高压器件和装置性能的关键因素之一，并成为其小型化的瓶颈所在。本项目采用离子注入与沉积等表面改性手段，在氧化铝陶瓷表面成功制备了TiO2、 Cr2O3等氧化物纳米复合介质层，解决了氧化铝注入过程中的频繁“打火”致使注入不均问题；实现了氧化铝表面电学性能调控，在不明显改变体电学特性的同时显著降低了表面电阻率、二次电子发射系数等电学参数；基于表面电学特性、陷阱能级特性分布和发展等特性阐明了表面电荷的时空演化规律。通过对半区覆盖Cr2O3纳米介质层的氧化铝陶瓷沿面闪络通道发展过程和表面电荷分布情况测试，验证了Cr2O3等纳米介质层对氧化铝陶瓷的沿面闪络性能的改进效能及机理。