Thermoelectric properties of Ca3–x Bi x Co4O9 + δ (0.0 ⩽ x ⩽ 1.5) ceramics
| Autor: | A. N. Kovalenko, Andrei Klyndyuk, E. A. Tugova, I. V. Matsukevich, N. S. Krasutskaya, A. A. Marova |
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| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Materials science General Chemical Engineering Metals and Alloys Analytical chemistry Mineralogy 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Thermal expansion Cobaltite Inorganic Chemistry chemistry.chemical_compound Thermal conductivity chemistry Electrical resistivity and conductivity Seebeck coefficient visual_art 0103 physical sciences Thermoelectric effect Materials Chemistry visual_art.visual_art_medium Ceramic 0210 nano-technology Solid solution |
| Zdroj: | Inorganic Materials. 52:593-599 |
| ISSN: | 1608-3172 0020-1685 |
| Popis: | We have studied the thermal, electrical, and thermoelectric properties of Ca3–x Bi x Co4O9 + δ (0.0 ≤ x ≤ 1.5) ceramics prepared by solid-state reactions. Phase-pure Ca3–x Bi x Co4O9 + δ solid solutions were obtained at x ≤ 0.3. The samples with 0.3 < x < 1.5 consisted of three phases: Ca2.7Bi0.3Co4O9 + δ, Bi2Ca2Co1.7O y , and Со3О4. The sample with the composition Ca1.5Bi1.5Co4O9 + δ consisted of two phases: Bi2Ca2Co1.7O y and Co3O4. The materials are p-type semiconductors with linear thermal expansion coefficients in the range (10.6–12.8) × 10–6 К–1. Their electrical and thermal conductivities are nonmonotonic functions of x, and their thermoelectric power increases with increasing x. The mixed-phase ceramics have been shown to have better thermoelectric properties: the highest thermoelectric power factor, ≈0.24 mW/(m K2) at T = 1100 K, is offered by the ceramics with x = 0.9–1.0, which contain nearly equimolar amounts of Ca2.7Bi0.3Co4O9 + δ and Bi2Ca2Co1.7O y . This power factor is 2.5 times that of the layered calcium cobaltite Ca3Co4O9 + δ and solid solutions based on it: 0.094–0.098 mW/(m K2) at the same temperature. |
| Databáze: | OpenAIRE |
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