کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7745611 | 1498258 | 2016 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Crystal structure and oxygen permeation properties of (La, Ba, Sr)(Co, Ta)O3-δ
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
الکتروشیمی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Crystal structure and oxygen permeation properties of (La, Ba, Sr)(Co, Ta)O3-δ Crystal structure and oxygen permeation properties of (La, Ba, Sr)(Co, Ta)O3-δ](/preview/png/7745611.png)
چکیده انگلیسی
To clarify the influence of Ta-substitution on oxygen permeability (JO2) as well as ion conductivity (Ïi) in a cobaltite perovskite, we investigated detailed crystal structures of (La0.4Sr0.6)(Co1-yTay)O3-δ(y = 0.0, 0.1, 0.2) and (La0.4BaxSr0.6-x)(Co0.8Ta0.2)O3-δ (x = 0.1, 0.2) at room temperature using synchrotron x-ray powder diffractometry (XRPD). The crystal structure of the (La0.4Sr0.6)(Co1-yTay)O3-δ was modified from cubic (Pm3Ì
m) to rhombohedral (R3Ì
c) by substituting Ta ions into perovskite B-sites because the tolerance factor deviates from unity with the Ta-substitutions. The tilting angle Ï of the CoO6 octahedra and strain parameters η estimated from the refined structural parameters suggest that the crystal structures of the Ta-substituted samples are improved to cubic at elevated temperatures of 800-900 °C. Although the lattice volume, the lattice free volume, the O-O bond lengths, and the bottleneck areas gradually increased concomitantly with increasing Ta content, the activation energies estimated from both JO2 and Ïi increased with Ta-substitution. Results suggest that the electrostatic interaction between Ta5 + and O2 â has greater impact than the crystallographic factors for the activation energy increase. Symmetry of the (La0.4BaxSr0.6-x)(Co0.8Ta0.2)O3-δ was improved from rhombohedral (R3Ì
c) to cubic (Pm3Ì
m) by substituting Ba ions for the A-sites because the tolerance factor approaches unity. The lattice constant, the O-O bond length, and the bottleneck area increased with the Ba-substitution. The lattice free volume depends on amount ratio between Co3Â + and Co4Â + cations in the samples. Both JO2 and Ïi increased with the Ba-substitution. The activation energy Ei of the Ïi slightly increased with the Ba-substitution.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Solid State Ionics - Volume 285, February 2016, Pages 180-186
Journal: Solid State Ionics - Volume 285, February 2016, Pages 180-186
نویسندگان
Isao Kagomiya, Yoshihito Shimono, Ken-ichi Kakimoto,