The extrusion of continuous lengths of YBa 2Cu 3O 7−x wire using hydroxypropyl methylcellulose

Abstract

Wires of YBa 2Cu 3O 7−x were fabricated by extrusion using a hydroxypropyl methylcellulose (HPMC) binder. As little as 2 wt.% binder was added to an oxide prepared by a novel co-precipitation process, to produce a plastic mass which readily gave continuous extrusion of long lengths of wire in a reproducible fashion. Critical temperatures of 92 K were obtained for wires given optimum high-temperature heat treatments. Critical current densities greater than 1000 A cm -1 were measured at 77.3 K using heat treatments at around 910°C for 10 h. These transport critical current densities, measured on centimeter-long wires, were obtained with microstructures showing a relatively dense and uniform distribution of randomly oriented, small YBa 2Cu 3O 7−x grains.