Al{sub 2}O{sub 3} additions for isothermal melt processing of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub {ital y}}

It is shown that additions of Al{sub 2}O{sub 3} (1.0 wt.{percent}) can significantly aid in the isothermal melt processing of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub {ital y}} (Bi{endash}2212). Al{sub 2}O{sub 3} additions provide a means for grain refinement of phases present in the partial melt. By limiting grain growth in the partial melt, solidification to form Bi{endash}2212 proceeds more efficiently, resulting in fewer secondary phases and improved transport properties. Aluminum does not substitute into the superconducting phase to any appreciable extent and is present in fully processed material as small, secondary grains of approximate composition Sr{sub 2{minus}{ital x}}Ca{sub {ital x}}AlO{sub {ital y}} or Bi{sub 2}Sr{sub 4{minus}{ital x}}Ca{sub {ital x}}Al{sub 3}O{sub {ital y}}Al{sub 2}O{sub 3} additions were applied to the isothermal melt processing of Bi{endash}2212 thick films and current leads. {copyright} {ital 1996 Materials Research Society.}