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研究了Bi-2223/Ag高温超导带材的前驱粉与后续热处理工艺之间的匹配问题。实验采用A,B,C3种不同的前驱粉。A粉是成分配比为2223的喷雾热分解单粉,B粉和C粉都是2212加CaCuOy组分的2223双粉。B粉和C粉的区别在于,2212加CaCuOy混合后的除碳处理工艺不同。B粉为800℃,3h,C粉为830℃,10h。利用激光粒度分析仪(RSA)和扫描电镜(SEM)对这3种前驱粉的粒度进行了表征,并用X射线衍射仪(XRD)对用这3种粉分别制成的带材经第1次热处理(HT1)后的2223成相率和相结构进行分析,从而找出它们各自对应的最佳HT1工艺。采用四引线法在77K,0T下测试经中间轧制和第2次热处理(HT2)后的临界电流(Ic),以确定其对应之最佳HT2工艺。RSA和SEM分析表明:A粉颗粒度明显细小,平均中径粒度为1.5μm,且粒径分布区域集中,B粉约3μm,粒径分布较分散,而C粉为4￣5μm。研究结果证明:前驱粉的特性直接影响着超导带材的最终超导性能。一种特定的前驱粉,对应着一种特定的最佳HT1和HT2工艺。只有在二者匹配良好前提下,才能使前驱粉的性能得以发掘。
The matching between the precursor powder of Bi-2223 / Ag superconducting tape and the subsequent heat treatment process was studied. Experiments using A, B, C3 kinds of different precursor powder. Powder A is a spray pyrolytic single powder with a composition ratio of 2223. Powder B and powder C are both 2212 plus 2223 double powders of CaCuOy. The difference between B powder and C powder is that the carbon removal process after 2212 plus CaCuOy is different. B powder is 800 ℃, 3h, C powder is 830 ℃, 10h. The particle sizes of these three kinds of precursor powders were characterized by laser particle size analyzer (RSA) and scanning electron microscope (SEM). X - ray diffraction (XRD) After heat treatment (HT1), the phase composition and phase structure of 2223 were analyzed to find their best HT1 process. The critical current (Ic) after intermediate rolling and the second heat treatment (HT2) was tested using a four-lead method at 77K, 0T to determine the best HT2 process for the corresponding HT2. The results of RSA and SEM showed that the particle size of A was obviously small and the average particle diameter was 1.5μm. The particle size distribution was concentrated. The B powder was about 3μm. The particle size distribution was more dispersed, while the C powder was 4-5μm. The results show that the properties of precursor powder directly affect the final superconductivity of the superconducting tape. A specific precursor powder, corresponding to a specific best HT1 and HT2 process. Only in the premise of a good match between the two can make the performance of the precursor powder to be explored.