ＴＦＡ‐ＭＯＤプロセスにおけるマルチターン式Ｒｅｅｌ‐ｔｏ‐Ｒｅｅｌ本焼成炉の開発

Abstract

We developed a new multi-turning system reel-to-reel (MT-RTR) system furnace with a vertical gas flow mode to increase the production rate of the crystallization step and attained a uniform reaction for the tapes in the multi-turn system. We fabricated YBCO films with different conditions including partial pressures of water vapor, the total pressure and the gas flow volume using the MT-RTR furnace with the vertical gas flow system, in order to investigate these influence of the processing parameters on the growth rate and the superconducting properties of the YBCO films. It was found that the growth rate of the YBCO layer increased under the conditions of the high gas flow rate, the low total pressure and the high partial water vapor pressure. As a result, 21 times higher Jc value was attained with the 17 times faster growth rate than that before optimizing the processing parameters in the crystallization step. This is thought to be due to the suppression of the coarsening of Y2Cu2O5 and CuO particles in the precursor film. Consequently, a high Ic,end-to-end value of 250 A/cm-w was achieved in a 5 m-long tape fabricated at a production rate of 3 m/h using only 2 lanes of the entire MT-RTR crystallization furnace originally designed for 10 lanes.