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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1014?·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。
In order to make the space charge accumulated by the spacecraft dielectric material in space environment timely release, a micron-grade powder modification method is added to the polyimide (PI) substrate to prepare a modified non-linear conductivity Characteristics of the new PI composite material. The conductivity of the PI composite was measured by a conductivity test system and a step-up method. The results show that the resistivity of the modified PI composites can be reduced to the order of 1014? Cm when the electric field intensity is 1.93 × 107 V / m. The nonlinear field conductivity threshold field strength ratio of the modified PI composites is lower than that of the PI composites The modified material is reduced by 50%, and the nonlinear conductivity is better. The nonlinear conductivity mechanism of modified PI composites is discussed. It is concluded that due to the addition of modifier, the number density of carriers in the material increases, When the electric field strength reaches a certain condition, the macroscopic nonlinear conductance phenomenon is formed due to the tunneling effect. Thus, the modified PI composite material has excellent nonlinear conductivity, which is beneficial to quickly release the space charge accumulated by the medium in the space environment.