Influence of the calcination procedure on the thermoelectric properties of calcium cobaltite Ca3Co4O9

Bresch, Sophie; Mieller, Björn; Selleng, Christian; Stöcker, Thomas; Moos, Ralf; Rabe, Torsten

doi:10.1007/s10832-018-0124-3

Cited by 18 publications

(19 citation statements)

References 45 publications

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“…The results showed that a stable composition of Ca 3 Co 4 O 9 powder was obtained at calcination at 1073 K for a higher soaking time between 20 and 30 h. However, some traces of cobalt oxide were still observed in the calcinated powder because of the Ca 3 Co 4 O 9 nonstoichiometry at room temperature. Bresch et al [25] investigated the effect of the calcination procedure on the thermoelectric properties of Ca 3 Co 4 O 9 powder using solid-state reaction technique. According to this study, no systematic study had been done on the thermoelectric properties affected by the calcination procedure.…”

Section: Introduction mentioning

confidence: 99%

Effects of calcination temperature and time on the Ca3Co4O9 purity when synthesized using starch-assisted sol-gel combustion method

2020

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Ca 3 Co 4 O 9 is a p-type semiconducting material that is well-known for its thermoelectric (TE), magnetic, electronic, and electro-optic properties. In this study, sol-gel autoignition was used to prepare Ca 3 Co 4 O 9 at different calcination temperatures (773, 873, 973, and 1073 K) and time (4, 6, 8, 10, 12, and 14 h) using starch as a fuel. The phase and microstructure of the prepared Ca 3 Co 4 O 9 powder were investigated. Thermogravimetry-differential thermal analysis (TGA) confirms that the final weight loss occurred at 1073 K to form Ca 3 Co 4 O 9 stable powder. The variable-pressure scanning electron microscopy (VP-SEM) images show that the size of powder particles increases from 1.15 to 1.47 μm as calcination time increases from 4 to 12 h, and the size remains almost constant thereafter. A similar pattern is also observed on the increment of the crystallite size and percentage of crystallinity with X-ray diffraction (XRD) analysis. The highest crystallinity is found about 92.9% when the powder was calcinated at 1073 K for 12 and 14 h with 458 and 460 Å crystallite size, respectively. Energy dispersive X-ray spectroscopy (EDS) analysis demonstrates that the calcinated powder has a high intensity of Ca, Co, and O with uniform distribution. High-resolution transmission electron microscopy (HRTEM) images prove that there is no distinct lattice distortion defect on the crystal structure.

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Section: Introduction mentioning

confidence: 99%

Effects of calcination temperature and time on the Ca3Co4O9 purity when synthesized using starch-assisted sol-gel combustion method

2020

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“…Previous studies have shown similar dependencies for oxide thermoelectric materials. 11,31 A higher degree of texture increases the electrical conductivity in ab-direction due to the anisotropy of the material. 22…”

Section: Effect Of Density and Texturementioning

confidence: 99%

“…This limits the sintering temperature and thereby the densification in the case of conventional sintering. 3,11 The anisotropy of the particle can be assigned to the polycrystalline material by texturing the microstructure. A detailed literature review about the texturing of Co349 can be found in our previous work 12 or by Prasad et al 13 Here we only focus on some aspects of texturing Co349.…”

Section: Introductionmentioning

confidence: 99%

Influence of pressure and dwell time on pressure‐assisted sintering of calcium cobaltite

et al. 2020

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“…Sophie Bresch et al drew the following conclusions by considering various process parameters: (a) The electrical conductivity varied linearly with the rate of densification and (b) the performance of Ca 3 Co 4 O 9 started to deteriorate at elevated calcination temperature [ 16 ]. The characteristics of Ca349 processed using a solid-state reaction (SSR), and SPS at 900 °C for 24 h were not affected by the cooling rate [ 17 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Heating Modes on Reactive Sintering of Ca3Co4O9 Ceramics

et al. 2021

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The traditional solid-state reaction method was employed to synthesize bulk calcium cobaltite (Ca349/Ca3Co4O9) ceramics via ball milling the precursor mixture. The samples were compacted using conventional sintering (CS) and spark plasma sintering (SPS) at 850, 900, and 950 °C. The X-ray diffraction (XRD) pattern indicates the presence of the Ca349 phase for samples sintered at 850 and 900 °C. In addition, SPS fosters higher densification (81.18%) than conventional sintering (50.76%) at elevated sintering temperatures. The thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA) performed on the precursor mixture reported a weight loss of ~25.23% at a temperature range of 600–820 °C. This current work aims to analyze the electrical properties (Seebeck coefficient (s), electrical resistivity (ρ), and power factor) of sintered samples as a function of temperature (35–500 °C). It demonstrates that the change in sintering temperature (conventional sintering) did not evince any significant change in the Seebeck coefficient (113–142 μV/K). However, it reported a low resistivity of 153–132 μΩ-m and a better power factor (82–146.4 μW/mK2) at 900 °C. On the contrary, the SPS sintered samples recorded a higher Seebeck coefficient of 121–181 μV/K at 900 °C. Correspondingly, the samples sintered at 950 °C delineated a low resistivity of 145–158 μΩ-m and a better power factor (97–152 μW/mK2).

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Influence of the calcination procedure on the thermoelectric properties of calcium cobaltite Ca3Co4O9

Cited by 18 publications

References 45 publications

Effects of calcination temperature and time on the Ca3Co4O9 purity when synthesized using starch-assisted sol-gel combustion method

Effects of calcination temperature and time on the Ca3Co4O9 purity when synthesized using starch-assisted sol-gel combustion method

Influence of pressure and dwell time on pressure‐assisted sintering of calcium cobaltite

Effect of Heating Modes on Reactive Sintering of Ca3Co4O9 Ceramics

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