▎ 摘　　要

NOVELTY - A magnesium diboride superconducting wire preparing method involves preparing an aqueous graphene oxide solution. The aqueous graphene oxide solution, boron powder and deionized water are uniformly mixed to obtain a mixed solution of boron powder and graphene oxide. The boron powder and the graphene oxide mixed solution are placed in vessel, the graphene oxide is thermally decomposed to graphene by hydrothermal reaction. The composite product is separated by centrifugation, and a precipitate is taken and vacuum dried to obtain graphene in-situ coated boron powder followed by fixing the magnesium rod in the center of the metal tube, taking two or more pieces into the metal tube to be placed in the metal tube, distributing single-core wires around the conductive metal core rod to obtain a tube-loading composite body, and processing tube-loading composite body into a multi-core wire and heat-treating to obtain a magnesium diboride superconducting wire. USE - Method for preparing magnesium diboride superconducting wire. ADVANTAGE - The method enables realizing the stable compounding and uniform coating of the graphene on the boron powder through the controllable graphene composite process, avoiding the shrinkage and agglomeration of the graphene in the traditional method, and providing superconducting wire with better grain boundary connectivity and a large graphene pinning center. DETAILED DESCRIPTION - A magnesium diboride superconducting wire preparing method involves preparing an aqueous graphene oxide solution. The aqueous graphene oxide solution, boron powder and deionized water are uniformly mixed to obtain a mixed solution of boron powder and graphene oxide. The boron powder and the graphene oxide mixed solution are placed in a hydrothermal reaction vessel, the graphene oxide is thermally decomposed to graphene by hydrothermal reaction, and the reduced product graphene is obtained. The composite product is separated by centrifugation, and a precipitate is taken and vacuum dried to obtain graphene in-situ coated boron powder followed by fixing the magnesium rod in the center of the metal tube, filling the graphite powder with the boron powder in situ between the magnesium rod and the metal tube, and sealing the ends of the metal tube to obtain a tube body, and rotating the tube body by swaging, drawing or hole rolling to obtain a single core wire, fixing the conductive metal core rod at the center of the other metal tube, and cutting off the single-core wire rod, taking two or more pieces into the metal tube to be placed in the metal tube, distributing single-core wires around the conductive metal core rod to obtain a tube-loading composite body, and processing tube-loading composite body into a multi-core wire by swaging, drawing or hole rolling, sealing both ends of the multi-core wire by a diffusion method, and heat-treating under a non-oxidizing protective atmosphere to obtain a magnesium diboride superconducting wire.