Prodn. of high temp. superconductor based on bismuth alkali-earth cuprate(s) - by partially melting powdered starting material, calcining, and cooling in inert gas atmosphere

摘要

Prodn. of a high temp. superconductor based on bismuth alkali-earth cuprates comprises: (a) partially melting a powdered starting material at a 1st process temp. (T1) above the melting point at an O2 partial pressure p(O2); (b) calcining at a 2nd process temp. (T2) at 830-870 deg.C at an O2 partial pressure p(O2); and (c) cooling to room temp. below 700 deg.C in inert gas atmosphere. The novelty is that partial melting at 1st process temp. (T1) is carried out in range of Tm (melting point of powdered starting material) K greater than T1 greater than Tm + 10K over a 1st process period (D1) of 1 hr. greater than D1 greater than 3 hrs. ADVANTAGE - High current density achieved.