Study on corona-resistance of polyimide-nano inorganic composites

A testing apparatus for voltage endurance of film materials subjected to partial discharges on its surface was developed according to IEC-343 and ASTM-2275. It consists of electrode unit, power supply unit and control unit, and has the function of testing simultaneously six group samples. The single chip computer is used to time and to switch off the circuit in which the sample is breakdown. The EEPROM is used to record the results. The corona-resistance of polyimide film before and after compound with nano-inorganic oxide is tested and the influence of the component and content on corona-resistance of material is researched. The Cp- /spl omega/ and tg /spl delta/ - /spl omega/ of samples both before and after corona aging are first studied by HP 4294 A and the surface morphology characterized by AFM.