| Epoxy resin has excellent electrical and mechanical properties,which is widely used as insulating material for high voltage electrical equipment.However,during the operation of electrical equipment,the charge will accumulate on the surface of insulating materials.The surface flashover will occur when the charge amount reaches the threshold value,which affects the normal operation of the equipment.Therefore,it is necessary to take effective measures to reduce the charge accumulation of insulating materials and increase the flashover voltage.As a convenient and efficient method,coating has a broad application prospect in improving the electrical properties of epoxy resin insulating materials.In this paper,the nano-SiC and nano-AIN were treated by plasma fluorination,and nano-fillled composite coating materials were prepared.The physicochemical properties and electrical properties of the samples were tested,the electrical properties include surface potential characteristics,volume conductivity and surface flashover voltage.Suitable nano-filler and coating material were selected through the test results,and the coating materials were coated on the epoxy resin with different thicknesses by the dip coating method.We tested the surface potential characteristics and flashover voltage of the samples.The results show that in the process of plasma fluorination,CF4 collides with high energy particles and dissociates into fluorine radicals,which graft onto nanoparticles as fluorine functional groups and replace the original hydroxyl groups.Because F element has higher electronegativity,it can change the charge distribution in the interface,increase the shallow traps and reduce the deep traps in the nanocomposites.At the same tine,the F element accelerates the charge dissipation,reduce the charge accumulation,and increase the flashover voltage of samples.With the increase of the nanofiller content the flashover voltage of the nanocomposites also increases.The flashover voltage of the samples doped 5 wt%fluorinated nano SiC reach the highest value.The samples coated with different thickness of fluorinated nano-SiC/epoxy composite coating have different surface charge dissipation rates.The thicker the coating is,the faster the surface charges disspate.When the sample contacts with the high voltage electrode,the possibility of surface flashover will reduce if there is lesser charge accumulation near the high voltage electrode.When the thickness of the coating is 600 ?m and the content of palsma fluorinated nano-SiC is 5 wt%,the flashover voltage of sample is 18.7%higher than that of uncoated samples.This shows that the plasma fluorinated nano-SiC/epoxy composite coating is a convenient and efficient method,and has a broad application prospect in improving the voltage level of GIS and GIL insulators. |
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