前驱粉粒度对Bi-2223带材微观结构和超导电性的影响研究

Microstructure and Superconducting of Bi-2223 Tape Prepared by Precursor Powder with Different Particle Size

摘要:

本文主要研究了前驱粉粒度对Bi-2223带材微观结构和超导电性的影响。通过调整溶液浓度和机械球磨,采用喷雾热分解方法制备了三种不同粒度的前驱粉(7um,2um,<1um)。三种粒度的前驱粉经热处理后的相组分均为Bi-2212,(Sr,Ca)_xCu_yO_d (AEC)和CuO。研究发现,AEC相的尺寸和含量均随着前驱粉粒度的减小而增加。在平均粒度为2um的前驱粉中,CuO相的含量和大小均为最小。采用这三种不同粒度的前驱粉制备的37芯带材,前驱粉平均粒度为2um的带材具有最高的临界电流,同时相对于另外两根带材,该带材中有最高的Pb-3221相和最少的AEC含量。研究结果表明,前驱粉粒度的大小主要影响了前驱粉中AEC和CuO两种相的大小和含量,进而导致了所制备带材的临界电流及芯丝中非超导相的变化。

Abstract:

The effects of particle size of precursor powder on microstructure and superconducting of Bi-2223 tape were investigated. Three kinds of precursor powders with different particle size (8μm, 2μm, <1μm) were prepared by spray pyrolysis method via adjusting the concentration of metal nitrates solution and ball milling. All powders were composed of Bi-2212, (Sr,Ca)_xCu_yO_d (AEC) and CuO phase after heat treatment. It was showed that AEC phase dimension and content increased with decreasing of particle size of precursor powders. However, the powder with average particle size of 2um had the minimal dimension and content of CuO phase. For 37-filaments Bi-2223 tapes fabricated by three kinds of precursor powders, the highest critical current (I_c) was achieved for powder with average particle size of 2um, which had highest (Bi,Pb)₃Sr₂Ca₂CuO_x(Pb-3221) and lowest AEC phase compared to other tapes. The results showed that particle size of precursor powders mainly affected dimension and content of AEC and CuO phase, which further caused difference of I_c and non-superconducting phases in Bi-2223 tape.