Mechanochemical Effects of Grinding on the Bi-Pb-Sr-Ca-Cu-O Superconductor

Abstract

The effects of mechanical grinding on the powder of the Bi-Pb-Sr-Ca-Cu-O superconductor (so-called “high T c phase”) were examined. The grain size of the powders decreased with increased grinding time accompanied by the degradation of crystallinity. Powders involving relatively lower crystal strain recovered their crystallinity as “high T c phase” by postheat treatment. But powders having relatively excessive crystal strain recrystallized as “low T c phase” and others. Such an effect reveals the metastability of the high T c phase under the condition of excessive crystal strain.