▎ 摘　　要

NOVELTY - Preparation of anti-corona material involves treating the surface of graphene oxide, adding graphene oxide to water and adding 2-4 %mass beta -(3,4-epoxycyclohexyl)ethyltriethoxysilane, centrifuging, performing surface treatment of graphene oxide, ultrasonically dispersing into an aqueous solution comprising sodium thiocyanate to obtain a suspension of graphene oxide, adding polyacrylonitrile powder, heating, cooling to obtain a polyacrylonitrile solution, mixing the graphene oxide suspension with the polyacrylonitrile solution, stirring , filtering to obtain polyacrylonitrile and graphene oxide mixed solution, preparing spinning dope, wet-spinning to prepare polyacrylonitrile and graphene oxide composite fibers, twisting polyacrylonitrile and graphene oxide composite fiber with glass yarn, half-stacking around a main insulation layer of the stator wire rod, wrapping the stator bar with a stripping strip, placing in the mold, hot-pressing, and removing the mold and stripping strip. USE - Preparation of anti-corona material used for slot portion of stator bar e.g. vacuum pressure impregnation stator bar of large motor. ADVANTAGE - The method enables preparation of anti-corona material with low resistance. DETAILED DESCRIPTION - Preparation of anti-corona material involves (i) treating the surface of graphene oxide, adding graphene oxide to water and adding 2-4 %mass beta -(3,4-epoxycyclohexyl)ethyltriethoxysilane as an aqueous silane coupling agent, centrifuging mixed solution and drying to obtain surface-modified graphene oxide, (ii) performing surface treatment of graphene oxide, ultrasonically dispersing into an aqueous solution comprising 50 %mass sodium thiocyanate to obtain a suspension of graphene oxide, adding polyacrylonitrile powder, controlling the temperature to 0-15 degrees C for 3-5 hours, heating the obtained aqueous solution to 60-80 degrees C and continuously stirring for 6-8 hours, cooling to obtain a polyacrylonitrile solution, mixing the graphene oxide suspension with the polyacrylonitrile solution, mechanically stirring at room temperature for 3-5 hours, filtering and defoaming to obtain polyacrylonitrile and graphene oxide mixed solution, (iii) preparing spinning dope using an aqueous solution comprising 12-14 %mass polyacrylonitrile, 0.1-15 %mass graphene oxide and 50 %mass sodium thiocyanate, (iv) wet-spinning to prepare polyacrylonitrile and graphene oxide composite fibers at a bath temperature of 8-12 degrees C, and a spinning speed of 5-10 m/minute, (v) twisting polyacrylonitrile and graphene oxide composite fiber with glass yarn, weaving into a cloth, removing the slurry and dewaxing to obtain a low-resistance semiconductor cloth having a thickness of 0.05-0.20 mm and a surface resistivity of 5x 102 to 5x 104 Omega , (vi) half-stacking around a main insulation layer of the stator wire rod with an adhesive to form a low-resistance anti-corona layer, (vii) wrapping a layer of stripping tape with holes on the entire surface of the stator bar, (viii) placing the stator bar in a vacuum pressure dipping paint tank and performing vacuum pressure dipping paint, (ix) removing stator strip with holes after stator dipping, (x) wrapping the stator bar with a stripping strip without holes, placing in the mold, and placing the mold in an oven and hot-pressing and curing, and (xi) cooling the mold, removing the mold and stripping strip of the coil.