【摘要】 采用人工掺杂Y 2 11相的方法以及熔融织构生长结合顶部籽晶工艺制备了不同 2 11粒子含量的准单畴熔融织构的YBCO块材料 ,样品致密度高 ,体密度大于 6 2g/cm3 ,机械强度好 ,振动样品磁强计测量结果表明 ,样品在温度 30K、磁场 0 6T下 ,其Jc 仍达到 1 2 3× 10 6A/cm2 .在温度 70K、磁场 2T条件下 ,Jc 仍高达 1 35× 10 4A/cm2 ,而且临界电流密度对磁场不敏感 .扫描电子显微镜分析也表明 ,Y 2 11相的人工掺杂 ,能改善织构样品的生长状况 ,减小微裂纹 ,同时 ,掺杂的Y 2 11粒子能作为强的钉扎中心 ,因此 ,这种工艺能精确地控制样品中Y 2 11粒子的含量 ,所制备的样品中Y 2 11粒子分布越均匀 ,尺寸越小 ,其钉扎效果越好 .从大量实验结果比较得出 ,1∶0 5是最佳的掺杂比例 .更多还原

【Abstract】 This paper describes the method of artificial doping Y\|211 phase and melt\|textured growth with a top\|seeded technique to prepare the quasi\|single crystal domain YBCO bulk materials with various Y\|211 particle contents.The specimens obtained have high density (more than 6 2?g/cm 3) and good mechanical toughness.The J c of specimens reaches 1 23×10 6?A/cm\+2 under 0 6T at 30?K and 1 35×10 4?A/cm 2 under 2 T at 70?K.The scanning electron microscope observation of specimens indicates that Y\|211 particles can improve the quality of melt\|textured YBCO superconductor and reduce the microcrack of specimens.Combining the microstructures with J c measurements shows that the smaller the particle size,the more homogeneous the particle distribution,the higher the pinning effectiveness.The best ratio of Y\|123 to Y\|211 for the superconductor specimens is 1∶0 5 in moles,in which the Y\|211 particles are uniformly distributed and their size is about 200?nm.更多还原