OXIDE SUPERCONDUCTING SUBSTANCE AND ITS PRODUCTION

摘要

PURPOSE:To obtain a Bi-Sr-Ca-Cu-O-based oxide superconducting substance having high critical temperature by blending a Sr compound with Ca compound, Bi compound and copper compound in a given ratio and calcining the blend in an oxygen-containing atmosphere at specific two stages. CONSTITUTION:A strontium compound (e.g. strontium carbonate) is blended with a calcium compound (e.g. CaCO3), a bismuth compound (e.g. bismuth oxide) and a copper compound (e.g. CuO) to give a compound shown by the formula [alpha/beta<=1.5;0.8<= alpha/gamma<=2; 0.25<=delta/(alpha+beta+gamma+delta)<=0.8; 0.5<=beta/delta<=0.85; 0.57<=(alpha+delta)/(alpha+ beta+gamma+delta)<=0.65]. Then the blend is calcined in an oxygen-containing atmosphere at 600-820 deg.C as first stage and then further burnt at 830-895 deg.C as a second stage to give a superconducting substance having high critical temperature of about 120K class and a small amount of impurity phase.