METHOD FOR SYNTHESIZING OXIDE FINE PARTICLE BY SPRAY DRYING

摘要

PURPOSE:To obtain Bi-based high-temp. superconducting ceramic fine particles consisting of a crystal structure of a high-Tc phase by spray-drying a nitrate soln., directly charging the obtained Bi-based superconductor starting material into a reaction furnace and heat-treating the material under specified conditions. CONSTITUTION:A nitrate soln. having a cationic composition shown by the general formula, BiuPbvSrwCaxCuyOz, is prepared (where u=1.4-1.9, v=0.1-0.8, w=1.8-2, x=1.95-2.3 and y=3-3.3). The soln. is spray-dried, and the dried powder is charged directly into the reaction furnace. The powder is heated at the rate of =15 deg.C/sec, and then heat-treated in the atmosphere at 835-845 deg.C for 1-2 hr. Consequently, the fine particles of the micron order in the ratio of about (Bi, Pb):Sr:Ca:Cu=2:2:2:3 consisting of a crystal structure of a high-Tc crystal phase having =110K Tc is obtained.