POWDER PROCESSING OF HIGH-TEMPERATURE CERAMIC SUPERCONDUCTOR TL2BA2CA2CU3O10

We have developed a technique to produce high quality Tl2Ba2Ca2Cu3O10 powders used for making superconducting wire, tape, lead, shield, and other large scale bulk applications. Starting with Tl2O3, BaO2, CaO, and CuO, we mix and grind these chemicals with a machine ball mill and then press the ground mixture into pellets. The pellets are sintered at about 895 degrees C for at least 30 h in an oxygen atmosphere. The sintered material is mainly the Tl2Ba2Ca2Cu3O10 compound. To get more homogeneous superconductor powders, we pulverize the sintered material and use a magnetic superconducting material selector to separate and grade the material. Finally, the top grade material has a phase purity of >98% and a T-c (r = 0) of 123-126K.