由于聚四氟乙烯(PTFE)具有优良的绝缘性、化学稳定性,因此常被用于航天器线缆制作.为了研究聚四氟乙烯材料沿面闪络特性,实验在正常大气压下对聚四氟乙烯材料两端施加直流高压,得到放电电压值以及电压、电流波形.通过整理、对比发现:随着闪络次数的增加,材料放电电压呈先增大后稳定的规律,闪络平均场强呈降低趋势.对实验结果进行分析,认为介质表面粗糙程度的改变、材料表面化学变化是影响聚四氟乙烯沿面闪络电压的重要原因.根据闪络次数对电压的影响提出了较为准确描述PTFE闪络电压的方法.%Polytetrafluoroethylene(PTFE) is often used in spacecraft cable production for its excellent insulation and chemical stability.To study the surface flashover characteristics of PTFE, we conducted experiments under normal atmospheric pressure, with the DC voltage applied at the two ends of the PTFE samples, and the discharge voltage value, voltage and current waveform were obtained.The results show that with the increase of the number of flashovers, the discharge voltage increases at first and then stabilizes, and the average field strength is reduced.It is concluded that the change of the surface roughness and the chemical properties of the surface are important factors that influence the surface flashover voltage.According to the influence of the number of flashovers on the voltage, a method to describe the PTFE flashover voltage is proposed.
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