Kinetic Studies of the Interfacial Reaction of the Ba2YCu3O6+x Superconductor with a CeO2 Buffer
| Autor: | Peter K. Schenck, Winnie Wong-Ng, Z. Yang, J. Frank, Lawrence P. Cook, Igor Levin |
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| Rok vydání: | 2007 |
| Předmět: |
Arrhenius equation
Phase boundary Chemistry Diffusion Activation energy Condensed Matter Physics Electronic Optical and Magnetic Materials Chemical kinetics Atomic diffusion symbols.namesake Reaction rate constant Materials Chemistry symbols Physical chemistry Electrical and Electronic Engineering Phase diagram |
| Zdroj: | Journal of Electronic Materials. 36:1293-1298 |
| ISSN: | 1543-186X 0361-5235 |
| Popis: | Interfacial reactions between the Ba2YCu3O6+x superconductor and the CeO2 buffer layers employed in coated conductors have been modeled experimentally by investigating the kinetics of the reaction between Ba2YCu3O6+x films and CeO2 substrates. At 810°C, the Ba2YCu3O6+x-CeO2 join within the BaO-Y2O3-CeO2-CuOx quaternary system is nonbinary, thereby establishing the phase diagram topology that governs the Ba2YCu3O6+x/CeO2 reaction. At a mole ratio of Ba2YCu3O6+x:CeO2 of 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 CuOx; on the CeO2 rich side, the four phases were determined to be Ba(Ce1−zYz) O3−x, BaY2CuO5, CuOx and CeO2. The Ba2YCu3O6+x/CeO2 reaction is limited by solid-state diffusion, and the reaction kinetics obey the parabolic rule, x = Kt1/2, where x = thickness of the reaction layer, t = time, and K = a constant related to the rate constant; K was determined to be 1.6 × 10−3 μm/s1/2 at 790°C and 4.7 × 10−3 μm/s1/2 at 830°C. The activation energy for the reaction was determined to be Eact = 2.67 × 105 J/mol using the Arrhenius equation. |
| Databáze: | OpenAIRE |
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