Processing and Fabication of YBa2Cu4O8 and YBa2Cu4O8/YBa2Cu3O(x) Composites.

摘要

Powders of YBa(sub 2)Cu(sub 4)O(sub 8)(''124'') were prepared via solid state reaction of Y(sub 2)O(sub 3), BaCO(sub 3), and CuO. The mixed precursors were heated in flowing oxygen of reduced total pressure, followed by cooling and annealing at 750(degree)C under ambient pressure oxygen. The procedure produced orthorhombic 124 as the main phase with YBa(sub 2)Cu(sub 3)O(sub x) (''123'') as a minor impurity phase. The phase purity improved and nearly phase-pure 124 was obtained upon annealing the as-calcined powder in flowing oxygen at 800(degree)C. 12 refs., 3 figs.