中文摘要：

为了使得在空间环境下航天器介质材料所积累的空间电荷能及时释放,采用向聚酰亚胺（PI）基体中添加微米级粉末改性方法,制备了一种改性后的具有非线性电导特性的新型PI复合材料.并利用电导测试系统且采用逐步升压的方法对该PI复合材料进行非线性电导测试研究.研究结果表明：在电场强度为1.93±107 V/m时,改性后的PI复合材料电阻率能降低至1014Ω＆#183;Cm数量级;改性后的PI复合材料非线性电导率阈值场强比未改性的材料降低了50％,非线性电导特性较好;对改性后的PI复合材料非线性电导机理进行了探讨,认为由于改性剂的加入,使得材料内部载流子数密度提高,当电场强度达到一定条件时由于隧道效应而形成宏观上的非线性电导现象.由此可得,改性后的PI复合材料有着优良的非线性电导特性,有利于快速释放掉空间环境状态下介质所积累的空间电荷.

英文摘要：

In order to ensure the accumulated space-charge of dielectric materials on spacecraft to discharge timely in the space environment, we adopted a method of adding the micron grade powder filler into polyimide （PI）, and developed a new type of modified PI composites which has non-linear conductivity characteristics. Moreover, we performed a non-linear conductivity test for the modified PI composite materials by a gradual boosting-voltage way with the conduc- tivity experinaent. The results show that, when the electric field intensity reaches 1.93 × 107 V/m, the resistivity of modified PI composite： materials will decrease into an order of magnitude of 1014 ~＇cm; the nonlinear threshold field intensity of the modified PI composites is reduced by 50% than that of pure PI, showing a better nonlinear conductivity behavior. Meanwhile, we discussed the non-linear conductivity mechanism of the modified PI composite materials, and found that the carrier concentration within the materials could be improved due to adding the modifying agent. When the internal electric-field reaches a certain value, the nonlinear-macroscopic conductivity phenomenon will be manifested because of the tunneling; effect. Thus, it can be seen that the modified PI composite materials have excellent non-linear conductivity characteristics and can discharge the accumulated space-charge of dielectric materials quickly in space environment.