Processing for long YBCO coated conductors by TFA-MOD process

The metal organic deposition (MOD) process of YBa₂Cu ₃O_7-X (YBCO) using metal trifluoroacetate (TFA) precursors is considered to be a strong candidate as a low cost fabrication process in coated conductors since the TFA-MOD process is a non vacuum process and can provide high J_c films. In order to develop long tape conductors using this process, the influence of the gas flow direction in the heat treatment was investigated. The J_c value decreases toward to leeward side in the case of the parallel gas flow condition. On the other hand, in the case of the perpendicular gas flow condition. The J_c value reveals uniformity in all over the tape and the high J_c level is maintained. In the case of long tape production, it was found that the perpendicular gas flow to the tape length is effective to fabricate the uniform films. It could minimize the influence of consumption of H₂O and generation of HF gas in the up-stream area to the leeward region. The J _c and I_c properties and these distribution of the YBCO tape fabricated by this method on CeO₂/IBAD-Gd₂Zr ₂O₇/Hastelloy is presented. Furthermore, a large scale equipment for the continues long tape process was developed based on the above findings. Consequently we have fabricated a 1 m long Y123 tape conductor by a reel to reel system. Even in the first trial, the uniform reaction for the entire length was recognized.