화학공학소재연구정보센터
Journal of Materials Science, Vol.29, No.12, 3113-3120, 1994
Preparation of YBCO-Ag Composites with Low-Carbon Contents by a Wet Method
YBa2Cu3O7-delta/Ag composites were prepared by a wet method, using readily available materials and a modification of the citrate method. This method allows for the addition of silver in soluble form to the YBCO soluble precursor and makes no use of nitrates, thus it allows for a smooth decomposition of the organic substance even in the presence of silver. After decomposition of the organic portion an effort was made to reduce the carbon content by using a gas flow containing N2 and O2 with 0.3% nitrogen oxide (NO). The carbon was substantially reduced by operating at high temperature. The pellets obtained from powder so formed were finally annealed at 950-degrees-C in oxygen and then characterized. By increasing the temperature of the NO-anneal a greater spreading of the silver among the YBCO grains was observed. The results show that by this method it is possible to obtain composites in which the only phases detected are YBa2Cu3O7-delta and metallic silver. Although further work needs to be performed on the final products to obtain higher densities and so to obtain improved grain coupling, the data described here open a new way for the production of YBCO-Ag composites with low carbon contents.