Fabrication and growth mechanism of YBCO coated conductors by TFA-MOD process

In the development for the coated conductors, the trifluoroacetates-metal organic deposition (TFA-MOD) process using the multi-coating method was applied to form thicker YBa2Cu3Oy (YBCO) films on the CeO2 buffered IBAD(Zr2Gd2O7)/Hastelloy tape. As a result, in the 5 times coated film with 1.38 mum in thickness, the J(c) and I-c values achieved to be 1.5 MA/cm(2) and 210 A, respectively. Then, we fabricated a 1 m long YBCO tape by the continuous reel-to-reel system. As a result, we confirmed the tape to be homogeneous by XRD analysis. Additionally, we report the theoretical analysis of YBCO growth during post-annealing in the TFA-MOD process considering both the diffusion in the gas boundary layer and the growth kinetics at the precursor/YBCO interface. This model reveals a basic idea of the growth mechanism to define the steady state growth rate, and could explain the experimental results. In addition, it predicts that the growth rate could be estimated from the partial pressure of the water vapor of the inlet gas. (C) 2003 Elsevier B.V. All rights reserved.