Effects of Optimum Annealing Time on Superconducting Properties of Bi2?xPbxSr2Ca2Cu3Oy System

✍ Scribed by Khalil, S.M.

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 384 KB
• Volume: 178
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/1521-396x(200004)178:2<731::aid-pssa731>3.0.co;2-s

✦ Synopsis

BSCCO superconducting ceramics of different compositions based on the system Bi 2± ±x Pb x Sr 2 Ca 2 Cu 3 O y (x 0.24, 0.26, and 0.28) were prepared by the conventional solid state reaction powder compacting method. BSCCO compounds have been subjected to atmosphere annealing treatments at 800 o C for different periods of time extended from 6 to 30 h. The effects of annealing time on the formed phases, critical transition temperature (T c o ) , microhardness (VHN) and surface microstructure of samples were investigated. The investigations proved that the most convenient time of annealing to obtain the highest peak intensity of the high-T c phase ( ), highest and sharpest transition T c o and maximum value of VHN is equal to 18 h. Prolongation of annealing time was associated with diminishing of all those parameters. This behaviour was attributed to the fact that this optimum annealing time (18 h) is characterized by the highest volume fraction of the (2223) phase formed in the compositions.