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用不同的熔化方法和后续热处理制备了BSCCO系超导体,研究了冷却速度、退火温度、退火时间和不同熔化方法对相变的影响,运用X射线衍射,光学显微镜,电子探针,差热分析,热重分析,导电性和抗磁性测量等分析了组织、结构和性能,结果表明,名义成分为Bi_2(Sr,Ca)_3Cu_2O_x的熔体在空气中凝固时,Bi_2(Sr,Ca)_3Cu_2O_(8+δ)(简称2212)超导相是较稳定的相;包含Bi_2(Sr,Ca)_2CuO_(6+δ)(简称2201)相的产物是易生成的亚稳相;在急冷条件下生成非晶后两者通过后续热处理可以转变成2212相,最佳退火温度在780-870℃间,非晶相也可转变成2201相,激光浮区熔化法(LFZM)制成的2201相退火后易转变成片状或纤维状的2212相,有利于改善超导相颗粒间的连接,提高临界电流密度
BSCCO superconductors were prepared by different melting methods and subsequent heat treatments. The effects of cooling rate, annealing temperature, annealing time and different melting methods on phase transformation were studied. X-ray diffraction, optical microscopy, electron probe, differential thermal analysis, The structure, structure and properties of Bi 2 (Sr, Ca) 3 Cu 2 O x melt were analyzed by thermogravimetric analysis, conductivity and diamagnetic measurement. The results show that when the melt with nominal composition Bi 2 (Sr, Ca) + δ) (referred to as 2212) superconducting phase is a relatively stable phase; the product containing Bi 2 (Sr, Ca) _2CuO_ (6 + δ) (referred to as 2201) phase is easily generated metastable phase; After the crystal after the two by subsequent heat treatment can be transformed into 2212 phase, the best annealing temperature between 780-870 ℃, the amorphous phase can also be transformed into 2201 phase, laser floating zone melting method (LFZM) made of 2201 after annealing The transformation into flake or fibrous 2212 phase is conducive to improving the connection between superconducting phase particles and increasing the critical current density