Tuning thermoelectric properties of Bi2Ca2Co2Oy through K doping and laser floating zone processing
| Autor: | Mehmet Gürsul, Bekir Özçelik, Tolga Depci, C. Özçelik, Andres Sotelo, M. A. Torres, M. A. Madre, Gizem Çetin |
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| Přispěvatelé: | Çukurova Üniversity, Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Gobierno de Aragón, European Commission, Universidad de Zaragoza, Mühendislik ve Doğa Bilimleri Fakültesi -- Petrol ve Doğalgaz Mühendisliği Bölümü, Özçelik, Can, Depci, Tolga |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Ceramics
Materials science Incongruent melting Annealing (metallurgy) Scanning electron microscope X ray diffraction Calcium compounds Resistivity Annealed fibers Annealing Performances Fabrication Electrical resistivity and conductivity Seebeck coefficient Phase (matter) Thermoelectric effect General Materials Science Layered cobaltites Composite material Laser floating zone Nacoo2 K-doping Physics Thermoelectric Electric power factor Doping Textures Oxides General Chemistry Power factors Condensed Matter Physics Strontium compounds Generators Chemistry Cobaltite Thermoelectric properties Power Power factor As-grown Scanning electron microscopy K-doped Substitution Thermoelectric oxides Bismuth compounds |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname Zaguán. Repositorio Digital de la Universidad de Zaragoza |
| Popis: | In the present study, thermoelectric Bi2Ca2-xKxCo2Oy ceramic materials (x = 0.0, 0.05, 0.075, 0.10, and 0.125) in different forms (called bulk, as-grown and annealed fibers) have been manufactured via a classical solid-state method and textured using the laser floating zone (LFZ) technique. The identification and characteristics of undoped and doped samples were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD patterns of all samples have shown great similarity, and the major peaks can be assigned to the Bi2Sr2Co2Oy thermoelectric phase, independently of the processing technique and K-doping. SEM-EDS have indicated the randomly oriented plate like grains of different sizes in bulk sample, evolving to longer and well-oriented grain structure through K-doping and LFZ. Because of the incongruent melting properties of compound, the high number of secondary phases formed in the as-grown samples. In order to reduce it, an annealing and K-doping process have been applied. The microstructural evolution is reflected on the electrical properties, and the lowest resistivity values are found in the annealed K-doped fibers. Seebeck coefficient is positive in all cases, pointing out to p-type conduction mechanism. These modifications led to PF values up to 0.162 mW/(K2m), obtained in 0.10 K-doped annealed fibers at 650 °C. The results used in the framework of this study are related to the MSc thesis of C. Özçelik. B.Ö thanks to Cukurova University Scientific Research Projects Unit for the project (FBA-2020-13007). M. A. Torres, M. A. Madre, and A. Sotelo acknowledge MINECO-FEDER (MAT2017-82183-C3-1-R, and Gobierno de Aragón-FEDER (Research Group T54-20R) for funding. Authors acknowledge the use of Servicio General de Apoyo a la Investigación-SAI, Universidad de Zaragoza. |
| Databáze: | OpenAIRE |
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