Influence of Ag addition on crystallization and microstructure of melt-grown single-grain YBa2Cu3O7 bulk superconductors
Influence of Ag addition on crystallization and microstructure of melt-grown single-grain YBa2Cu3O7 bulk superconductors
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DOI：
10.1088/0953-2048/14/7/311
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发表时间：
2001-07
影响因子：
3.6
通讯作者：
P. Diko;G. Krabbes;C. Wende
中科院分区：
文献类型：
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作者：
P. Diko;G. Krabbes;C. Wende
采用光学显微镜图像处理技术，定量分析了以YBa_2Cu_3O_7（Y123）+0.24Y_2O_3 + Ag_2O为前驱体，不同Ag_2O添加量，在不同炉冷速率下生长的YBaCuO/Ag复合材料的显微结构。在熔体中的临界平均Ag浓度的开始和稳定状态的Ag颗粒形成的估计。较高的生长速率导致Ag颗粒在生长方向上的伸长和排列。B型单晶体结晶被鉴定为发生在超单晶体组合物中。Monoclonal和hypermonoclonal类型的Ag颗粒，这在尺寸和形态上不同，进行了区分，并提出了它们的形成机制，同时考虑到Ag和Y2 O3添加对相平衡的影响，并考虑到一定的溶解度的Ag在Y123。
The microstructure of YBaCuO/Ag composite materials prepared from precursors YBa2Cu3O7(Y123) + 0.24Y2O3 + Ag2O with different amounts of Ag2O addition, grown at different furnace cooling rates, was analysed quantitatively by image processing of optical microscopy images. The critical average Ag concentration in the melt for the start and the steady state of Ag particle formation was estimated. A higher growth rate causes elongation and alignment of Ag particles in the growth direction. Type B monotectic crystallization was identified to take place in the hypermonotectic compositions. Monotectic and hypermonotectic types of Ag particles, which differ in size and morphology, were distinguished and the mechanisms of their formation proposed, taking into account the influence of both Ag and Y2O3 additions on the phase equilibria and considering a certain solubility of Ag in Y123.