The Surface Fluorination Of Crosslinked Polystrene And Its Vacuum Surface Flashover Performance Reasearch

The applied electric field strength is much lower than the solid dielectric material bulk breakdown strength and vacuum electrical strength when the surface of the insulating material in the vacuum discharge?vacuum surface flashover?.The insulating performance is often subject to vacuum flashover phenomenon constraints.A large number of researches about vacuum surface flashover phenomenon of various materials indicated that:?1?The surface flashover voltage is closely related to the surface properties of the material.Surface modification can significantly improve the flashover performance of the material.?2?Under the same experimental conditions,the vacuum flashover voltage of fluoropolymer is highest.Inspired by the above experimental study,cross-linked polystyrene?CLPS?the first choice of materials used in vacuum electrical equipment was chosen in this article.The surface of CLPS was modified by fluorination.The research contents of this paper are followed:?1?CF₄ plasma excited by dielectric barrier discharge system and FEVE fluorocarbon resin was used for cross-linked polystyrene surface modification.?2?The surface properties of CLPS were investigated,including surface morphology observation by Super-depth microscope and atomic force microscopy?AFM?,surface composition analysis by Fourier transform infrared spectroscopy?FTIR?and X-ray photoelectron spectroscopy?XPS?.?3?The water contact angle,surface resistivity,surface charge attenuation and flashover performance of CLPS were measured,the influence of surface microtopography and surface fluorine on surface dielectric properties were discussed.?4?The characteristic and effect of the two kinds of fluorination modification methods were compared and discussed.The main findings are:?1?Surface microtopography parameters Ra of the sample first increases then decreases with treatment time increases and surface protuberances increases,fluoride groups are introduced into material surface and mainly in the form of C-F.?2?Plasma fluorination decreases the surface resistivity of the material to and increases the surface charge trapping capability,vacuum surface flashover voltage of CLPS is improved by more than 50%by this method.The increase of surface microtopography parameters Ra and the introduction of C-F bond lead to the increase of vacuum flashover voltage.?3?The surface of original material surface is covered by macromolecular chain containing a large amount of fluorine atoms.the surface water contact angle is increased,the surface fluorocarbon coating can increase the surface charge decay rate and improve the surface flashover voltage,the thicker the coating,the faster the charge decay rate,the surface potential decay by44.8%at most.When the proportion of FEVE resin and curing agent is 6:1,the modification effect is the best and the flashover voltage is the largest.?4?The aging effect of the plasma modified samples is obvious,after 10 days of aging,the surface static water contact angle has picked up,but the fluorocarbon resin coating surface exhibits excellent aging resistance,the water contact angle does not change substantially.