کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1626028 | 1516443 | 2007 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Preparation and structures of the La1âxKxCo1âxNbxO3 (x = 0-l) system
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
فلزات و آلیاژها
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چکیده انگلیسی
The La1âxKxCo1âxNbxO3 system was performed by conventional solid state reaction technique using metal oxides. By DSC analysis, the activation energy of crystallization of the powders with x = 0.3 is 388.4 kJ/mol. The crystal structure of the compound reveals a transition from rhombohedral to cubic, and then to orthorhombic structure as the amount of the potassium niobate (KNbO3) increases. It is found that the structure of the samples with x < 0.3 is similar to that of lanthanum cobaltate (LaCoO3), while at the compositions with 0.7 â¥Â x â¥Â 0.3, the structure transforms to cubic. Finally, with x â¥Â 0.7, the structures were similar to that of KNbO3. According to the results of selected-area-diffraction (SAD) patterns and X-ray diffraction (XRD) identifications, the lattice parameters were calculated. The direction of superlattice structure along [2 1 0] was found for x = 0.5 as identified from SAD patterns. The dielectric constants were measured with cubic structure. Dielectric constant (K) decreases with increasing x.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Alloys and Compounds - Volume 430, Issues 1â2, 14 March 2007, Pages 205-211
Journal: Journal of Alloys and Compounds - Volume 430, Issues 1â2, 14 March 2007, Pages 205-211
نویسندگان
Tzu-Wei Huang, Yee-Shin Chang, Guo-Ju Chen, Yen-Hwei Chang,