FABRICATION OF SUPERCONDUCTING YBA2CU3O7-X FIBERS BY THE SOL-GEL METHOD USING METAL ALKOXIDES

Superconducting YBa2Cu3O7-x fibers were fabricated by the sol-gel method using modified metal alkoxides. To prepare a heterometallic alkoxide as a precursor of a homogeneous and viscous sol, Y and Cu alkoxides were modified with ethyl acetoacetate (EAA) and ethylenediamine (en), respectively. Their structures were determined by FT-IR and EXAFS. The heterometallic alkoxide was synthesized by partial hydrolysis of the modified alkoxides and was further hydrolyzed and concentrated to obtain a viscous sol. This sol had good spinability and was spun into gel fibers by a spinning apparatus. The gel fibers had a high oxide content of 61 wt. %. The fiber, fired at 950-degrees-C for 10 h in O2, had only closed pores and a dense structure. T(c) (onset) of this fiber was 94 K.