SUPERCONDUCTING THICK-FILMS BASED ON BI-PB-SR-CA-CU NITRATE PASTES, SCREEN-PRINTED ON ALUMINA AND ZRO2 BUFFERED ALUMINA

This study demonstrates the preparation of screen printed Bi-(Pb)-Sr-C a-Cu-oxide superconducting films starting from a paste, based on spray dried nitrate solutions. The spray dried precursor powder was studied using TGA-DTA and XRD. It is shown that decomposition to oxides occur s at temperatures more than 200 degrees C lower than those in the resp ective oxide/carbonate mixture. The thick film properties were studied using XRD, SEM-EDAX and electrical resisitivity measurements. The fil ms, coated on alumina substrates, showed clear superconducting transit ion below 60K, but did not reach zero resistivity. Films coated on alu mina with a ZrO2 buffer layer and sintered at 835 degrees C showed T-c , 0 up to 77 K.