Recent Progress on R&D of Advanced TFA-MOD Process for Coated Conductors

Abstract

The recent progress in R&D of TFA-MOD process for the coated conductors is reviewed. On the effort towards fabricating high I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> tape, a new process to prevent crack formation in the thick film, which is the intermediate annealing between calcination and crystallization steps, was developed. Additionally, control of the composition from the 123 stoichiometric ratio, especially for Ba-poor composition, is found to be effective to improve J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> values of the films. Consequently, the extremely high Ic value of 692 A was obtained. On the other hand, a reel-to-reel system has been applied to fabricate long tapes. The high Ic value of 250 A/cm-w in a 4 m long tape and the reasonable long tape of 25 m with 100 A/cm-w were obtained. Additionally, it was newly found that the humidity control to be low P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</sub> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">O</sub> in the coating room is effective to suppressing the degradation of the Jc characterization.