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Specific Features of Phase Formation and Properties of Compounds La2W1 + xO6 + 3x (x ~ 0; 0.11–0.22)1статья
- Авторы: Shlyakhtina A.V., Lyskov N.V., Kolbanev I.V., Vorob’eva G.A., Shchegolikhin A.N., Voronkova V.I.
- Журнал: Russian Journal of Electrochemistry
- Том: 59
- Номер: 1
- Год издания: 2023
- Издательство: Maik Nauka/Interperiodica Publishing
- Местоположение издательства: Russian Federation
- Первая страница: 60
- Последняя страница: 69
- DOI: 10.1134/s1023193523010081
- Аннотация: The hexagonal solid solution La2W1 + xO6 + 3x (x ~ 0.11) and the orthorhombic low-temperaturephase β-La2WO6 (La2W1 + xO6 + 3x (x = 0)) are synthesized by the methods of preliminary mechanical activation of oxides followed by high-temperature synthesis at 1400°С, 4 h. In addition, by using the method ofcrystallization from solution, a single crystal of the La2W1 + xO6 + 3x (x ~ 0.22) composition isostructural toLa2W1 + xO6 + 3x (x ~ 0.11) is grown. Both ceramics and the single crystal are studied by the methods of Ramanspectroscopy, thermal analysis, and thermogravimetry. Their conductivity is studied by impedance spectroscopy in dry and humid air. The hexagonal single crystal La2W1 + xO6 + 3x (x ~ 0.22) demonstrates strong luminescence in the IR region, in contrast to the hexagonal ceramics La2W1 + xO6 + 3x (x ~ 0.11) and the β-La2WO6ceramics with the orthorhombic structure. The polycrystalline La2W1 + xO6+3x (x ~ 0.11) ceramics is foundto be more stable under redox conditions as compared with the single crystal. The conductivity of the hexagonal single crystal La2W1 + xO6 + 3x (x ~ 0.22) is of the oxygen-ionic nature and lower than the conductivity ofceramics La2W1 + xO6 + 3x (x ~ 0.11) due to its perfect structure. The contribution of the protonic componentof conductivity is absent for both the hexagonal solid solution La2W1 + xO6 + 3x (x ~ 0.11) and the single crystalLa2W1 + xO6 + 3x (x ~ 0.22), their conductivity being of the purely ionic nature with the close values of activation energy (0.89 and 1.08 eV, respectively). The synthesized β-La2WO6 ceramics demonstrates a small contribution of the protonic conductivity in humid air equal to ~1 × 10–6 S/cm at 600°С, which is close to theconductivity of the earlier studied strontium-doped solid solution La1.96Sr0.04WO6 – δ based on β-La2WO6.
- Добавил в систему: Воронкова Валентина Ивановна