Effects of plasma modified micro-Al<inf>2</inf>O<inf>3</inf> on surface partial discharge and insulation aging of micro-Al<inf>2</inf>O<inf>3</inf>/epoxy resin composites

Abstract

The research on partial discharge at the surface of the insulation material is very necessary, which will cause electrical aging and insulation failure. Due to the strong ability of anti-electrical tree of micron aluminum oxide, it is widely added to the epoxy resin matrix to enhance the resistance on electrical insulation aging ability of the insulating composite material. In order to strengthen the interface bonding between the micron aluminum oxide and epoxy resin, the surface modification of the micron aluminum oxide is necessary, the modification of the low temperature plasma and coupling agent was introduced in this article. In the experiment, 2μm α — aluminum oxide is selected as the filler material, after the micron aluminum oxide is modified by coupling agent, and then put the micro aluminum oxide in the low-temperature plasma region which is produced by dielectric barrier discharge at the atmospheric pressure, the modified micro aluminum oxide is filled into bisphenol-A epoxy resin to prepare composites, and test the characteristics of compound materials which is modified by single coupling agent and compound modification. The cross sectional morphology of micron aluminum oxide/epoxy resin under different modification methods is observed by the scanning electron microscopy (SEM), and the filling and dispersion of the micron aluminum oxide/epoxy resin composites are compared and analyzed. The surface partial discharge initial voltage of the composite under different modification modes are measured by step up method to study the effects of composite modification on the electrical properties of the micron aluminum oxide/ epoxy resin composites. The composite internal electrical tree growth is observed by Transmission electron microscopy (TEM) under needle plate electrode condition, and study the electrical insulation aging which is caused by the micron aluminum oxide/epoxy resin internal electrical tree under the composite modification. Based on the experimental results described above, after the micron aluminum oxide was modified by the low temperature plasma and coupling agent, we can discuss the effect of the electrical aging which was caused by the surface partial discharge of the epoxy resin on insulation property. The results show that the micron aluminum oxide modified by the low temperature plasma and coupling agent has a good ability to inhibit the insulation aging which was caused by the surface partial discharge of the epoxy resin.