Direct Preparation of Fine Powders of the 80K Superconducting Phase in the Bi-Ca-Sr-Cu-O System by Spray Pyrolysis.

超声波喷雾热解技术制备了Bi_2Ca_1Sr_2Cu_2O_x微细超导粒子，验证了通过改变温度分布、相应金属硝酸溶液的初始浓度和流速来控制最终产物粒子性能的可行性。实验结果表明，溶液液滴蒸发和热分解产生的超导粒子存在形态控制的可能性。这些粉末在840oc下烧结后，在TAU_c=104K处出现了超导跃迁偏移。此外，使用该粉末在银板上或两个银板之间制备了厚膜。在200 kg/cm^2的压力下将粉末压在银板上或两个银板之间，并在855^ cc下热处理30 min。在冷却至室温后，再次在840^ C下对银板上的所得膜进行热处理62小时。得到的厚膜偏移温度为104K。另一方面，夹在Ag板之间的薄膜，冷却后在855^ C下热处理40小时，显示出80K的偏移温度。

The preparation of fine superconductive Bi_2Ca_1Sr_2Cu_2O_x particles by ultrasonic spray-pyrolysis technique verified the feasibility of controlling the properties of the final product particles by changing the temperature profile, initial concentration of corresponding metal nitrate solution and the flow rate. The experimental results shows that there exists the possibility of morphological control of superconductive particles generated from the evaporation and thermal decomposition of solution droplets.The body sintered from these powders at 840^ﾟC showed the offset of superconducting transition at TAU_c=104K. Furthermore, the thick films have been prepared on a Ag plate or between two Ag plates using the powders. The powders were pressed on a Ag plate or between two Ag plates at 200 kg/cm^2 and heat-treated at 855^ﾟ for 30 min. The resultant films on a Ag plate were again heat-treated at 840^ﾟC for 62 hr after the cooling to room temperature. The thick films obtained showed the offset temperature of 104K. On the other hand, the films sandwiched between Ag plates, which were heat-treated also at 855^ﾟC for 40 hr after the cooling, showed the offset temperature of 80K.