热处理工艺对溶胶-凝胶法制备YBa2Cu3O7-δ粉体性能影响

Influence of Heat Treatment on Properties of YBa2Cu3O7-δ Powders Prepared by Sol-Gel Method

以钇，钡，铜的醋酸盐为起始原料，乙醇为溶剂，二乙烯三胺、丙酸为络合剂，制备了稳定的YBa2Cu3O7-δ（YBCO）溶胶。溶胶经70℃蒸发溶剂后，形成凝胶，经500℃热分解，850℃高温烧结，随后在500℃氧气条件下退火后，获得了临界转变温度为92K的YBCO超导粉体。利用差热仪分析了凝胶热分解过程，通过X射线衍射仪对粉体进行了物相分析，利用扫描电镜观察粉末的粉体形貌。实验表明，热分解速度影响最终YBCO粉体形貌：快速热分解有利于获得细小、均匀的YBCO超导粉体。

With acetate as starting materials, alcohol as solvent, diethylenetriamine and propionic acid as complexing agents, stable YBa2Cu3O7-δ（YBCO）sol was prepared. After the solvent evaporation by heating at 70℃, the black gel was obtained and subsequently pyrolyzed at 500℃.The pyrolyzed precursor powders were sintered at 850℃ and annealed at 500℃ in oxygen atmosphere, producing the YBCO superconducting powders with critical transition temperature of 92K. Differential Thermal Analysis was used to analyze the pyrolysis process; X-ray Diffraction was used to analyze the powder phase-structure; and Scanning Electronic Microscopy was used to observe the powder morphology. Results show that rapid pyrolysis and low sintering temperature are favorable for obtaining small-sized, homogenized powders.