Development of Low AC Loss TFA-MOD Coated Conductors
Development of Low AC Loss TFA-MOD Coated Conductors
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低交流损耗TFA-MOD涂层导体的开发
DOI：
10.1016/j.phpro.2014.09.025
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Y. Shiohara
中科院分区：
文献类型：
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作者：
K. Katayama;T. Machi;T. Nakamura;Y. Takagi;K. Nakaoka;M. Yoshizumi;T. Izumi;Y. Shiohara
由于TFA-MOD工艺能够以较低的成本生产出高性能的YBCO涂层导体，因此具有广阔的应用前景。将YBCO超导体应用于变压器、电力电缆等电力设备中，需要降低长导线的交流损耗。多晶化工艺是继划片工艺之后发展起来的一种降低交流损耗的有效方法。我们已经开发了使用化学蚀刻的增强过程。然而，MOD衍生的CC，容易在化学蚀刻过程中损坏，由于在YBCO层中的孔的存在，导致临界电流（Ic）的退化和弱的分层强度。因此，难以使用化学蚀刻工艺将MOD衍生的CC刻划成长长度的1 mm宽的细丝。因此，我们已经研究了使用受激准分子激光器而不进行化学蚀刻的划线工艺。在本研究中，我们将P'值定义为照射的激光功率[J]除以加工速度[m/s]的函数。研究了P'值与划线结果的关系。我们发现我们可以把C.在P'值较大的情况下，具有足够的深度。此外，我们发现随着P'值的进一步增加，Ic降低。在P'为9[J/（m/s）]下，通过受激准分子激光划线工艺将5 mm宽的短样品分成10根细丝。该样品显示滞后损失降低到1/10，这可以从使用细丝数量的理论预测中预期。IC-降解被抑制为28%，这小于使用化学蚀刻的划线样品的IC-降解（IC-降解为38%）。随后，我们将该技术应用于100米长的YBCO连铸机。100 m长MOD衍生CC的磁滞损耗在多次拉伸后降低到1/10（1/丝条数）。
TFA-MOD process is expected to be promising for future applications since it can produce high performance YBCO coated conductors (CCs) with low cost. Applying YBCO CCs to the power electric devices such as transformers and power cables, the reduction of alternating current (AC) loss for long wire is necessary. Multi-filamentation process, which is one of the most effective approaches for AC loss reduction, has been developed by the scribing process. We have developed the filamentation process using chemical etching. MOD derived CCs are, however, easily damaged in the chemical etching process due to existence of pores in a YBCO layer, resulting in critical current (Ic)-degradation and weak delamination strength. Consequently, it is difficult to scribe MOD derived CCs into 1mm-wide filaments for long length using the chemical etching process. Accordingly, we have studied a scribing process using an excimer laser without chemical etching. We defined P’ value in this study as a function of irradiated laser power [J] divided by processing speed[m/s]. We studied relationship between the P’ value and the results of scribing. It was found that we could scribe the C.C. with a sufficient depth in the condition of large P’ value. Furthermore, we found that theIcwas degraded with further increase of the P’ value. A 5 mm wide short sample was divided into 10 filaments by the excimer laser scribing process at the P’ of 9[J/(m/s)]. The sample revealed reduction of the hysteresis loss down to 1/10 which could be expected from a theoretical prediction using the numbers of the filaments.Ic-degradation was suppressed as 28%, which was smaller than that of the scribed sample using chemical etching (Icdegradation was 38%). Subsequently, we applied the technique to a 100m long YBCO CC. The hysteresis loss of the 100m long MOD derived CC was reduced down to 1/10 (1/the number of filaments) after the multi-filamentation.