Development of high-Ic processing for low cost YBCO coated conductors by multi-turn reel-to-reel crystallization large furnace for TFA-MOD process
Development of high-Ic processing for low cost YBCO coated conductors by multi-turn reel-to-reel crystallization large furnace for TFA-MOD process
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DOI：
10.1016/j.phpro.2012.03.445
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
Y. Takagi;Y. Takahashi;K. Nakaoka;M. Yoshizumi;N. Akagi;S. Takahashi;T. Izumi;Y. Shiohara
中科院分区：
文献类型：
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作者：
Y. Takagi;Y. Takahashi;K. Nakaoka;M. Yoshizumi;N. Akagi;S. Takahashi;T. Izumi;Y. Shiohara
三氟乙酸酯(TFA)-金属有机沉积(MOD)制备的YBCO涂层导体有望有许多应用，主要是由于成本效益。为了降低成本，需要较高的集成电路和生产率，以每平方厘米成本计算。本文以TFA-MOD的转化过程为重点，对提高集成电路的性能和生产率进行了研究。采用多圈卷对卷(RTR)浸渍镀膜-焙烧系统制备了所需厚度的YBCO前驱体薄膜。对前驱体薄膜进行了包括中间退火在内的不同条件下的热处理。用多圈RTR系统对中间退火后的样品进行了晶化处理。对转化炉进行了改造，采用了较高的气体流量、较低的总压等条件，加快了YBCO的生长速度，使结晶过程的产率提高到15m/h。采用中间退火法后，集成电路的性能比未进行中间退火法制备的提高了约30%。X射线θ-2θ衍射分析表明，中间退火态样品中的YBCO(005)峰强度是未中间退火态样品的1.5倍。中间退火影响了结晶度和显微组织，导致了较高的IC。然后，将改进的结晶工艺应用于长带材的制备。以15m/h的速度制备的205m长的YBCO镀膜导体在整个带材上表现出高而均匀的IC性能，IC(min.)=372A/cm-w@77K，S.F.，标准偏差=15.2A(3.7%)。通过将54m长的带子(199.5 A/5 mm宽)分成5个细丝，对横向的均匀性进行了分析，确定了每个细丝(1 mm宽)的IC值是均匀的；
Trifluoroacetates (TFA) –metal organic deposition (MOD) derived YBCO coated conductors are expected for many applications mainly due to cost-efficiency. High Ic and production rate are required for cost reduction in terms of $/Am. Improvement of Ic performance and production rate has been studied in this work, focusing on the conversion process of TFA-MOD. YBCO precursor films with desired thickness were prepared by using the multi-turn reel-to-reel (RTR) -system of dip-coating and calcination. The precursor films were heat treated under different conditions including the interim annealing. Crystallization process was performed on the interim annealed samples by using a multi-turn RTR system. The conversion furnace was modified so that improved conditions such as higher gas flow rate, lower total pressure can be used, which improved the production rate in crystallization process to 15 m/h by accelerating YBCO growth rate. Adopting the interim annealing, Ic property increased about 30% compared with that prepared without the interim annealing. X-ray θ-2θ diffraction analysis showed that; the peak intensities of YBCO (005) in interim annealed samples were 1.5 times stronger compared with those prepared without the interim annealing. The interim annealing affected the crystallinity and microstructure, resulting in high Ic. Then, the improved process for crystallization was applied to long tapes fabrication. A 205 m-long YBCO coated conductors fabricated at 15 m/h with interim annealing showed high and uniform Ic performance throughout the tape; Ic(min.)=372 A/cm-w@77K, s.f., standard deviation = 15.2 A (3.7%). Uniformity along transverse direction was also analyzed by striating a 54 m long tape (199.5 A/5 mm-widths) into 5 filaments and, the Ic value of each filament (1 mm-width) was confirmed to be uniform; 24.3-32.9 A.