Developments of low cost coated conductors by multi-stage CVD process

A low cost and a high-speed production process must be required for a realization of a YBCO coated conductor, especially in the electric power field applications. A multi-stage CVD is one of the most promising processes for manufacturing a coated conductor with a low cost and a high-speed production. Recent progress in developments of long YBCO coated conductors by multi-stage MO-CVD process and their properties would be described. The 203-m-long IBAD substrate (PLD-CeO2/IBAD-GZO/HastelloyC) was used for preparing the long YBCO tape. The tape traveling speed at the each passing was 50 m/h and number of passing was 14 times. We applied a 12-stage CVD hot-wall chamber system for preparing YBCO layer. As a result, the end-to-end Ic of 92.8 A (77 K self-field, 1 μV/cm criteria) was obtained. The Ic(A) x L(m) value corresponded to 18.8 kA. The n-value of the tape remained 15.5. Then we measured the Ic distribution for longitudinal direction at 0.5 m intervals. The obtained data showed us that the average Ic was roughly 140-150 A, however, we confirmed some low Ic regions, which is about 65-100 A. The origin of the low Ic regions was summarized. Concerning a high performance YBCO development, we achieved Ic of 294 A/cm by introducing a multi-temperature and composition control process