Preparation of high-T/sub c/ superconducting thick films and power conducting tubes by a low-pressure plasma spraying

Superconducting thick films of YBaCuO and BiSrCaCuO systems have been prepared using a low-pressure plasma spraying technique. The chemical composition of the deposits was very close to that of the spraying powders. After postannealing the films showed zero resistance temperatures, T/sub c/ of approximately 90 K for YBaCuO and approximately 60 K for BiSrCaCuO. Superconducting power tubes were successfully produced by a low-pressure plasma spraying. 100-200- mu m-thick YBaCuO superconducting films were deposited on the outer surface of the Ni-plated Cu tubes. After postannealing at 930 degrees C for 1 h the films exhibited T/sub c/ of 85-90 K. An improved film preparation process in which a flux layer is coated on the Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub x/ matrix layer by a low-pressure plasma spraying has been developed. Enhanced critical currents have been achieved by this process.<
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