Investigation on starting solution of TFA-MOD process for high-speed production of YBCO coated conductors

We have developed a new starting solution consisting of non-fluorine (F-free) yttrium salt, barium trifluoroacetate and copper octylate with focusing on a high-speed production of YBa2Cu3O7-y (YBCO) coated conductors by the trifluoroacetate-metal-organic deposition (TFA-MOD) method. High critical current density (J(c)) was recognized in the YBCO films fabricated on CeO2 buffered ion-beam assisted deposition (IBAD)-Gd2Zr2O7/Hastelloy substrates from the new starting solution at a wide range of the heating rates in the calcination process (2 -> 25 degrees C/min, 2.3 -> 2.4 MA/cm(2)). Additionally, any degradation of J(c) performance (higher than 2 MA/cm(2) at 77 K, self-fields) up to about 0.4 mu m per single coating was not observed in the YBCO films fabricated from the new starting solution at the heating rate of 5 degrees C/min in the calcination process. The relationship between fluorine contents in the single coating film and J(c) performance of the YBCO films suggested that the fluorine content in the single coating film determines the quality (bulk density, uniformity, etc.) of the precursor film. (C) 2009 Elsevier B.V. All rights reserved.