【摘要】 通过基于共沉淀工艺的双粉法制备了Bi_1.76Pb_0.34Sr_1.93Ca_2.0Cu_3.06O_8+δ（Bi-2223）前驱体粉末。在这一过程中,首先单独制备了Bi_1.76Pb_0.34Sr_1.93CaCu_2.06O_8+δ（Bi-2212）和CaCuO₂ （实际相组成为Ca₂CuO₃和CuO）粉末,并分别进行了烧结。通过调节共沉淀工艺过程中的pH值,获得了颗粒尺寸不同的CaCuO₂粉末,然后将Bi-2212与CaCuO₂粉末按照相组成1:1进行混合,并装入Ag包套中,通过一系列的旋锻、拉拔和轧制工艺,获得设计尺寸的Bi-2223带材。比表面积测试表明随着pH值从3.0增加到5.0和6.5,获得CaCuO₂粉末的平均颗粒尺寸从1.10mm减小到0.75和0.60mm。通过扫描电镜对不同尺寸CaCuO₂颗粒制备的Bi-2223生带、第1次热处理和后处理之后带材的相组成和分布进行了表征。结果表明,适当尺寸的CaCuO₂颗粒可以避免团聚现象的出现,因此有利于高载流性能带材的获得。最终通过进一步调节带材的尺寸,1#带材的性能最高,电流密度达到了约12 200 A·cm^-2。更多还原

【Abstract】 Bi_1.76Pb_0.34Sr_1.93Ca_2.0Cu_3.06O_8+δBi-2223) precursor powders were fabricated with a two-powder route based on co-precipitation process. During this process, Bi_1.76Pb_0.34Sr_1.93CaCu_2.06O_8+δ（Bi-2212） and CaCuO₂（with the actual phase composition of Ca₂CuO₃ and CuO） powders were first synthesized and calcined separately, and then mixed together before packed into Ag sheath. By adjusting the pH values during the co-precipitation process, CaCuO₂ powders with different average particle sizes of about 1.10, 0.75, and 0.60 mm were obtained. Then single filament Bi-2223/Ag tapes were fabricated by powder in tube（PIT） process with precursor powders obtained by mixing the different particle sized CaCuO₂ powders and well-calcinated Bi-2212 powders. The influences of CaCuO₂ particle size on microstructure, phase evolution dynamics and superconducting current capacity of sintered Bi-2223 tapes were studied. Results show that due to higher uniformity of Ca₂CuO₃ and CuO distribution in filaments, clustering of secondary phases and insufficiently reacted areas are effectively avoided. Therefore, higher current density of ～12 200 A·cm^-2 is obtained for the 1# tape by further optimizing the final dimension of the tapes.更多还原