Howard Wayne Jacobson

The production of high performance YBa 2 Cu 3 O 7 using nitrogen dioxide

Energy dispersive x-ray spectroscopy (EDS) was used to show that the elemental homogeneity of YBa{sub 2}Cu{sub 3}O{sub 7} powders can be improved substantially by heating the powder in a nitrogen dioxide-containing atmosphere (e.g., 950 {degree}C), followed by annealing in oxygen at 950 {degree}C, and slow-cooling to room temperature. The improved homogeneity results in a substantially larger flux exclusion signal for the NO{sub 2}-treated powder, as measured by both ac and dc techniques. The experimental results suggest a mechanism which involves the formation of a small amount of molten Ba(NO{sub 3}){sub 2}, which acts as a flux that dissolves the constituents and reprecipitates them as high purity YBa{sub 2}Cu{sub 3}O{sub 7}.

The production of high performance YBa sub 2 Cu sub 3 O sub 7 using nitrogen dioxide

Energy dispersive x-ray spectroscopy (EDS) was used to show that the elemental homogeneity of YBa{sub 2}Cu{sub 3}O{sub 7} powders can be improved substantially by heating the powder in a nitrogen dioxide-containing atmosphere (e.g., 950 {degree}C), followed by annealing in oxygen at 950 {degree}C, and slow-cooling to room temperature. The improved homogeneity results in a substantially larger flux exclusion signal for the NO{sub 2}-treated powder, as measured by both ac and dc techniques. The experimental results suggest a mechanism which involves the formation of a small amount of molten Ba(NO{sub 3}){sub 2}, which acts as a flux that dissolves the constituents and reprecipitates them as high purity YBa{sub 2}Cu{sub 3}O{sub 7}.