Surface and gas phase reactions arising with epoxy exposed topartial discharges

摘要

The relative effects of gas phase and surface reaction processes,occurring in air and nitrogen during the partial-discharge-induceddegradation of epoxy resin specimens, were investigated. For dischargesin both air and nitrogen, ESCA (electron spectroscopy for chemicalanalysis) surface analyses indicated that the oxygen within the epoxymatrix structure itself contributes markedly to the formation of certaintypes of degradation products, which in turn cause a transition in thedischarge mechanism. The initially occurring large-pulse(short-risetime) discharges (300 to 500 pC) were replaced by small-pulse(long risetime) discharges (1.0 to 0.5 pC) and eventually by true glowdischarges when the specimens were tested to sufficiently long exposuretimes