Kinetics Studies of the Interfacial Reactions of the Ba2Ycu3O6+x Superconductor With CeO2 Buffer

Published

October 16, 2007

Author(s)

Lawrence P. Cook, Winnie K. Wong-Ng, Z Yang, Peter K. Schenck, Igor Levin, Julia Frank

Abstract

Interfacial reactions between the Ba2YCu3O6+x superconductor and the CeO2 buffer layer employed in coated conductors have been modeled experimentally by investigating the kinetics of the reaction between Ba2YCu3O6+x and CeO2. At 810 C and pO2 = 100 Pa, the Ba2YCu3O6+x - CeO2 join within the BaO-Y2O3-CeO2-CuOx quaternary system is non-binary. At a mole ratio of Ba2YCu3O6+x : CeO2 = 40 : 60, a phase boundary was found to separate two four-phase regions. On the Ba2YCu3O6+x-rich side of the join, the four-phase region consists of Ba2YCu3O6+x, Ba(Ce1-zYz)O3-x, BaY2CuO5, and Cu2O; on the CeO2 rich side, the four phases were determined to be Ba(Ce1-zYz)O3-x, BaY2CuO5, Cu2O and CeO2. The Ba2YCu3O6+x /CeO2 reaction is limited by solid-state diffusion, and the reaction kinetics obeys the parabolic rule, x = Kt1/2 (where x is thickness of the reaction layer, t is time, and K is a constant related to the rate constant); K was determined to be 1.2 x 10 2 mm/min1/2 at 790 C and 3.6 x 10 2 mm/min1/2 at 830 C. The activation energy for the reaction was determined to be Eact = 2.44 x 105 J/mol using the Arrhenius Equation.

Citation

Journal of Electronic Materials

Volume

36

Issue

10

Pub Type

Journals

Keywords

coated conductor, interfacial reaction of CeO₂, kinetics of reaction, solid-state diffusion

Citation

Cook, L. , Wong-Ng, W. , Yang, Z. , Schenck, P. , Levin, I. and Frank, J. (2007), Kinetics Studies of the Interfacial Reactions of the Ba₂Ycu₃O_6+x Superconductor With CeO₂ Buffer, Journal of Electronic Materials (Accessed September 18, 2024)