航空低气压条件下磁控溅射PTFE表面耐电性能

Surface Electrical Properties of Magnetron Sputtered PTFE Under Aeronautical Low Pressure Conditions

聚四氟乙烯(PTFE)具有良好的耐热性能和机械性能,已逐渐成为航空线缆的主流绝缘材料,为满足多电飞机供电系统电压等级提升及航空条件下复杂环境绝缘要求,亟须进一步提升线缆绝缘耐电性能。采用磁控溅射TiO2制备了5种PTFE样品,测试了改性样品的水接触角及电导率,通过闪络及电老化实验对试样表面耐电性能进行分析,基于表面陷阱分布对磁控溅射的影响机理进行解释。结果表明,改性后样品表面疏水性提升,电导率降低,随磁控溅射时间增长PTFE表面闪络电压及抗电老化性能先提升后下降,效果在改性45 min时最好。溅射后提升了绝缘表面电荷捕获能力,抑制放电发展过程,使闪络电压提高;深陷阱捕获电荷形成反向电场,自由电荷注入-脱出过程受到抑制,PTFE耐电老化性能得到提升。

Polytetrafluoroethylene(PTFE)has good heat resistance and mechanical properties and has gradually become the mainstream insulation material for aviation cables.To satisfy the requirements of increased voltage level for the power supply system of more electric aircraft and the insulation in the complex environment and aviation conditions,it is urgent to further improve the electrical resistance of cable insulation.In this paper,five kinds of PTFE samples were prepared by magnetron sputtering TiO2.The water contact angle and conductivity of the modified samples were tested.The electrical resistance of the sample surfaces was analyzed by flash and electrical aging experiments,and the mechanism of the effect of magnetron sputtering was explained based on the surface trap distribution.The results show that the surface hydrophobicity of the modified samples is improved and the conductivity is reduced.With the growth of magnetron sputtering time,the flashover voltage and anti-electro-aging properties of PTFE surface are first enhanced and then decreased,and the effect is best at 45 min of modification.The surface charge trapping capability is enhanced after splashing inhibits the development of discharge,resulting in an increase in flashover voltage.Deep traps capture charges,forming a reverse electric field that suppresses the injection-extraction process of free charges and improves the electrical aging resistance of PTFE.