کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5458865 | 1516167 | 2017 | 27 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
High-temperature defect thermodynamics of nickel substituted double-perovskite cobaltite PrBaCo2âxNixO6âδ (x = 0.2)
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
فلزات و آلیاژها
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The double perovskite praseodymium cobaltites PrBaCo2âxNixO6âδ, where 0.1 â¤Â x ⤠0.3, were obtained by combustion of organo-metallic precursors and shown to have a tetragonal structure with the crystalline lattice parameters a â 3.91 and c â 7.63 Ã
consistent with electron compensation 2Co3+ = Ni2+ + Co4+ of Ni2+ impurity centers. The oxygen content (6 - δ) vs. log(pO2) dependencies were measured by a coulometric titration technique for x = 0.2 at 650-950 °C and oxygen pressure variations within 10â10 - 0.6 atm. The reductive decomposition of the cobaltite is found to take place at δ = 1.13. The experimental data were utilized in order to derive partial thermodynamic functions of oxygen that govern defect equilibration. The oxygen partial enthalpy ÎH¯O and entropy ÎS¯O are found to exhibit strong changes near (6 - δ) = 5. The observed behavior is explained in frameworks of the defect formation model, which involves reactions of charge disproportionation of Co3+ cations, oxygen exchange with the gas phase and oxygen disordering over O2 and O3 structural positions.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Alloys and Compounds - Volume 727, 15 December 2017, Pages 778-784
Journal: Journal of Alloys and Compounds - Volume 727, 15 December 2017, Pages 778-784
نویسندگان
B.V. Politov, A. Yu. Suntsov, I.A. Leonidov, M.V. Patrakeev, V.L. Kozhevnikov,