Controlled Overpressure Processed Bi2223 Wires for Power Applications

Progress in the performance of the controlled overpressure (CT‐OP) processed (Bi,Pb)2Sr2Ca2Cu3Ox (Bi2223) wire is reviewed. Optimization of the CT‐OP processing improved microstructure of Bi2223 wires and increased their critical current (Ic) by greater than 60% compared to normal pressure processing. The CT‐OP processing effectively removed pores and cracks. The SEM show CT‐OP wires had very dense, uniform, and well connected Bi2223 grain. Densification of the CT‐OP wires prevents liquid nitrogen penetration during long term exposure to liquid nitrogen of them for use in power cable applications. Ballooning caused by trapped nitrogen, that expands when warming up to room temperature, doesn’t occur in CT‐OP wires. These high performance levels in CT‐OP wires have enabled commercial level applications such as power cables, magnets and motors.