The Bi1.8Pb0.4Ca2Sr2Cu3Oy superconductor is prepared by a citrate precursor method. Nitrate salts of the constituent metals are dissolved in deionized water, and citric acid and ethylene glycol are added. The pH of the solution is adjusted to 6.8. The solution is then dried at 80°C, pyrolyzed at 200°C, calcined at 810°C, pressed into pellets and sintered at 860°C for 20 min, and lowered to 850°C for different periods and cooling in the furnace or quenching in the air. The highest Tc(zero) is 114 K, observed in a sample which is sintered for 24 hr and resintered for 96 hr with furnace cooling. The X-ray diffraction pattern shows that it contains 95% high Tc phase of Bi2-xPbxCa2Sr2Cu3Oy superconductor.
Journal of Solid State Chemistry 109(2), pp.227-230