Monitoring Sintering / Densification and Crystallization / Grain-Growth in Tl-Based High Temperature Superconductors by Electrical Conductivity Measurements

Abstract
An “in situ” electrical resistance method has been used to monitor sintering to best achieve a high percentage of Tl-2223 structure. By this means, the sequential formation of syntactic intergrowths, 2201, 2212 and 2223 structures, was followed as a function of temperature, time, seeding and gaseous atmosphere. At 895°C, slight melting assists the formation of ∼95% pure 2223; the presence of carbonate is probably deleterious.