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顶部籽晶PMP法是一种熔融处理技术,对于制备高Jc的YBCO块材具有很好的效果,而定向凝固技术在制备具有良好取向的单晶时也经常用到。将这两种工艺结合起来(称作定向顶部籽晶PMP法(DTSPMP))可以制备具有良好单畴的YBCO块材。本文分析了籽晶传递作用和液相中溶质浓度的变化,研究了温度梯度对晶体取向和大晶粒持续生长的影响。使用扫描电镜分析了抽拉速率对微观组织的作用,结果表明在较低的抽拉速率下可以获得更大尺寸的单畴组织和细小弥散的211颗粒。
The top seed PMP process is a melt process that works well for the production of high Jc YBCO blocks, and directional solidification techniques are often used to prepare single crystals with good orientation. Combining these two processes, termed Directional Top Seeding PMP (DTSPMP), allows the preparation of YBCO blocks with good monodomain. In this paper, the effect of seed transfer and the change of solute concentration in the liquid phase are analyzed. The effect of temperature gradient on the crystal orientation and the continuous growth of large grains is also studied. Scanning electron microscopy (SEM) was used to analyze the effect of drawing rate on the microstructure. The results show that larger size single domain and finely dispersed 211 particles can be obtained at a lower drawing rate.