Long tape processing for coated conductors by multiple-stage CVD method

The multiple-stage CVD method is the promising technology, which can be realized for rapid and long formation of YBCO tape. In earlier researches, we have fabricated the six-stage CVD system, and successfully developed 100 m long YBCO tape at the deposition rate of 10 m/h. However, over 500 m long wires are required for the practical applications. In order to achieve this, we have studied the multi-coating of YBCO layer at further high-speed deposition. Five layers of YBCO tape were fabricated on roll milled non-textured Ag substrate directly. Each layer was deposited by the six-stage CVD system at deposition rate of 25 m/h. After each deposition, temperature of YBCO tape went down to room temperature. The distribution of Jc was within 25% and its value is the same as single coating one. No significant degradation of Jc was observed. From these results, it was indicated that the multiple-stage CVD system, which equips more reactors serially, is effective way for making longer YBCO tapes