材料期刊网

在柔性衬底上制备的Bi-2212（Bi2Sr2CaCu2O8＋x）超导厚膜在高场低温下有高的临界电流密度、可塑性好、易加工成材等特点,因而有广阔的应用前景.所以制备低成本、高性能的Bi-2212厚膜技术已经成为此类高温超导材料实用化的关键.本文系统的研究了采用Bi系超导粉前驱化学溶液的方法进行Bi-2212超导厚膜的制备和表征.对制备超导厚膜过程中的关键步骤做了系统的研究,主要包括局部熔融烧结温度、固相烧结温度、匀胶机最高转速、涂层的厚度等对超导转变温度和转变宽度的影响.我们得出最佳的烧结温度和固相温度分别是888℃、845℃,并发现随着匀胶机转速和涂层厚度的增加,超导膜的转变温度逐步提高,当最高转速为4000r/min,涂层厚度设定为七层,制备出的超导膜R～T曲线的第二个相转变点消失了.制备出的超导膜的转变温度在90K左右.与此同时还进行了XRD、SEM测试表征.最终可以得到均匀平整无裂纹的高质量Bi-2212超导厚膜.

The Bi-2212 superconductive thick film fabricated on flexible substrate was equipped with the excellent performance of high threshold current density, deformability and easiness to manufacture which guarantee the wide range of application. So, the techniques of fabricating Bi-2212 thick film with excellent performance have become the critical point for practical application of Bismuth Cobalt oxide high temperature superconducting material. The article reported the approaches of fabricating the Bi-2212 thick film based on the method of precursor chemical solution and the analysis of surface characteristics. It discusses the critical steps and factors during the process of fabricating, including the influence of partial melting of sintered temperature, solid-phase sintering temperature, speed of spin coating machine and the thickness of the film on the point and the width of the superconducting transition temperature. According to the results of experiments, we conclude the optimal temperature of solid-phase sintering temperature and partial melting of sintered temperature are 888 ℃ and 845℃. The results show that the superconducting transition temperature increases as the speed of spin coating increases. When the speed of spin coating reaches the peak of 4000r/rain and the thickness of the film equals to 7 layers, the transition point of second phase on R- T graph disappeared. The superconducting transition temperature is 90K. The analysis results of surface characteristics by XRD and SEM indicated the smooth surface performance of Bi-2212 thick film without cracks.