纳米氧化钛复合改性提升聚醚酰亚胺真空沿面闪络特性的物理机制分析  

Physical Mechanism Analysis of Improvement of Vacuum Surface Flashover Performance by Nano-TiO_(2) Composite Modification

作　　者：曾嘉凯 李倬凡 张妍 刘霞[1] 杨柳青[1] 刘文凤[1] 迟晓红 程璐 ZENG Jiakai;LI Zhuofan;ZHANG Yan;LIU Xia;YANG Liuqing;LIU Wenfeng;CHI Xiaohong;CHENG Lu(State Key Laboratory of Electrical Insulation and Power Equipment(Xi’an Jiaotong University),Xi’an 710049,Shaanxi Province,China)

机构地区：[1]电力设备电气绝缘国家重点实验室(西安交通大学),陕西省西安市710049

出　　处：《中国电机工程学报》2024年第14期5810-5820,I0032,共12页Proceedings of the CSEE

基　　金：国家重点研发计划项目(2021YFB2400604);陕西省重点研发计划(2020ZDLGY09-10)。

摘　　要：聚醚酰亚胺是重要的航天器用绝缘材料。提升聚醚酰亚胺的沿面绝缘性能并探究沿面闪络的物理机制具有重要意义。该研究通过纳米氧化钛复合改性有效地将聚醚酰亚胺的真空沿面闪络电压提高19.25%。通过表征纳米复合前后材料的表面形貌、表面释气和表面电荷输运特性发现,表面气体吸附量随着TiO_(2)含量的升高而增大,而深陷阱能级和表面电阻率与闪络电压呈正相关关系。分析认为,纳米复合改性后气体吸附特性变化不足以影响真空沿面闪络。纳米复合改性提高真空沿面闪络电压的根本原因在于适量的TiO_(2)能提高材料的表面电阻率和深陷阱能级,二者的提高阻碍电极处电荷的注入和表面电子发射,进而造成电子倍增过程受阻。当电子倍增过程受阻时,介质表面需要更大的能量去释放更多的内部溶解气体或使介质分解产生更多气体以便碰撞电离形成足够强度的电子崩,因此沿面闪络电压有所提升。Polyetherimide(PEI)is an important insulating material for aerospace applications.It is of great significance to improve surface insulating properties of PEI and to investigate the physical mechanism of surface flashover.In this study,vacuum surface flashover voltage of PEI is effectively improved by 19.25%via nano-TiO_(2) composite modification.By investigating the surface morphology,surface outgassing characteristics,and surface charge transport characteristics of PEI before and after the modification,it can be found that gas adsorption capacity is improved with the increase of the mass fraction of TiO_(2),while deep trap level and surface resistivity are positively correlated with the flashover voltage.The analysis suggests that the changes in surface gas adsorption capacity is not enough to affect vacuum surface flashover.The essential reason for the improvement of vacuum flashover voltage by nano-TiO_(2) composite modification is that the increase of surface deep trap level and surface resistivity hinders the charge injection at the electrode and electron emission of the surface,thus preventing the electron multiplication process.When the electron multiplication process is suppressed,the dielectric needs more energy to promote the escape of dissolved gas inside the dielectric or the decomposition of dielectric,so that the gas collision ionization is sufficient to enhance the electron avalanche,thus leading to the improved flashover voltage.

关 键 词：聚醚酰亚胺 纳米复合 真空闪络 表面陷阱 表面释气 

分 类 号：TM215[一般工业技术—材料科学与工程]