Compatibility of C5F10O with common-used sealing materials: An experimental study

摘要

C 5 F 10 O has been widely studied as a promising environmentally friendly substitute to SF 6 in power equipment. Up to now, the environmentally friendly gas insulated equipment developed still uses the same sealing materials as SF 6 gas insulation equipment. However, whether these sealing materials are chronically compatible with C 5 F 10 O has always been a fundamental problem that perplexes the industry and academia. In this study, a thermally accelerated aging experiment on four rubber materials contacted with C 5 F 10 O/N 2 was carried out. During the experiment, aged rubbers were analyzed using scanning electron microscopy and x-ray photoelectron spectroscopy to obtain the surface morphology characteristic and element composition. The gas samples were collected periodically and detected through gas chromatography mass spectrometry. Meanwhile, the degradation of the rubbers’ mechanical property is tested to figure out their long-term compatibility with C 5 F 10 O/N 2 mixtures. Surface analysis of the rubber samples showed that after thermal accelerated aging, F in the form of C–F bonding and metal fluorides were detected on the surface of the ethylene propylene diene monomer (EPDM), nitrile butadiene rubber (NBR), chloroprene rubber (CR), and methyl vinyl silicone rubber (VMQ), which did not exist in origin samples. The main gaseous decomposition products of C 5 F 10 O include CO, CO 2 , C 3 F 6 , and C 3 F 7 H, and the concentration when coexisting with rubber is significantly higher than that in the control group. The compression performance of aged rubbers all reduced, and the compression performance of EPDM and NBR is better than that of CR and VMQ. The experimental results proved the incompatibility between C 5 F 10 O and these four rubbers, while EPDM and NBR showed less deterioration in compression properties and could be more suitable for the C 5 F 10 O power equipment.