کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1531772 | 995847 | 2006 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Oxygen permeability, electronic conductivity and stability of La0.3Sr0.7CoO3-based perovskites
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
مواد الکترونیکی، نوری و مغناطیسی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Oxygen permeability, electronic conductivity and stability of La0.3Sr0.7CoO3-based perovskites Oxygen permeability, electronic conductivity and stability of La0.3Sr0.7CoO3-based perovskites](/preview/png/1531772.png)
چکیده انگلیسی
The electrical properties of perovskite-type (La0.3Sr0.7)1âyCoO3âδ (y = 0-0.03) and La0.3Sr0.7Co0.8M0.2O3âδ (M = Al, Ga), promising parent materials of dense mixed-conducting membranes for oxygen separation, were studied in the oxygen partial pressure range from 10â14 to 0.5 atm. The steady-state oxygen permeation fluxes through cobaltite ceramics at 973-1223 K are limited by both bulk ionic conductivity and surface exchange kinetics. The substitution of cobalt with Al3+ or Ga3+ increases cubic perovskite unit cell volume, oxygen deficiency and Seebeck coefficient, whereas the thermal expansion, p-type electronic conductivity and oxygen permeability decrease. The creation of A-site cation vacancies, compensated by Co4+ formation, leads to higher p-type electronic conductivity and thermal expansion at temperatures above 700 K, whilst the ionic transport in A-site deficient cobaltite is lower than that in La0.3Sr0.7CoO3âδ. Reducing oxygen pressure down to approximately 10â5 atm results in transition into brownmillerite-type phases having essentially p(O2)-independent electrical properties until decomposition, which occurs at p(O2) values 102 to 104 times higher compared to CoO/Co boundary. The average thermal expansion coefficients of cobaltite ceramics in air are (15.9-19.6) Ã 10â6 Kâ1 at 300-750 K and (27.9-29.7) Ã 10â6 Kâ1 at 750-1240 K.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Materials Science and Engineering: B - Volume 134, Issue 1, 25 September 2006, Pages 80-88
Journal: Materials Science and Engineering: B - Volume 134, Issue 1, 25 September 2006, Pages 80-88
نویسندگان
V.V. Kharton, E.V. Tsipis, A.A. Yaremchenko, I.P. Marozau, A.P. Viskup, J.R. Frade, E.N. Naumovich,