Preparation of high-performance Ca3Co4O9 thermoelectric ceramics produced by a new two-step method

Madre, M. A.; Costa, F.M.; Ferreira, N.M.; Sotelo, A.; Torres, Miguel; Constantinescu, G.; Rasekh, Sh.; Díez, J. C.

doi:10.1016/j.jeurceramsoc.2013.01.029

Cited by 82 publications

(60 citation statements)

References 34 publications

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“…The very important increase on the Seebeck coefficient values obtained in the as-grown materials is due to the considerable amount of oxygen vacancies produced by this processing method, as reported in previous works [31]. On the other hand, the decrease observed in the Seebeck coefficient when the textured samples are annealed, is in agreement with the results obtained in thermoelectric materials which have shown that at high temperatures oxygen diffuses inside the bulk ceramic material to fill the vacancies, decreasing the Seebeck coefficient values [32]. The highest Seebeck different phases, which can react to produce the desired one by annealing, as can be seen in Fig.…”

Section: Methodssupporting

confidence: 90%

Processing effects on the thermoelectric properties of Bi2Ca2Co1.7Ox ceramics

Rasekh¹,

Constantinescu²,

Madre³

et al. 2014

Bol. Soc. Esp. Ceram. Vidr.

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Section: Methodssupporting

confidence: 90%

Processing effects on the thermoelectric properties of Bi2Ca2Co1.7Ox ceramics

Rasekh¹,

Constantinescu²,

Madre³

et al. 2014

Bol. Soc. Esp. Ceram. Vidr.

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“…Micrographs of the surfaces have been used to analyze the different phases and their distribution. Apparent density measurements have been performed on several samples for each composition after sintering, using 4.677 g/cm 3 as theoretical density [29]. Oxygen content was determined in some of the annealed materials by cerimetric titrations, as described elsewhere [7].…”

Section: Methodsmentioning

confidence: 99%

Decrease of electrical resistivity in Ca3Co4O9 thermoelectric ceramics by Ti doping

Torres

Rasekh

Bosque

et al. 2014

J Mater Sci: Mater Electron

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Ca 3 Co 4-x Ti x O 9 polycrystalline thermoelectric ceramics with small amounts of Ti have been prepared by the classical solid state method. X-ray diffraction data have shown that Ca 3 Co 4 O 9 is the major phase, with small amounts of the Ca 3 Co 2 O 6 one. Moreover, they show that Ti has been incorporated into these two phases. Electrical resistivity decreases, compared with the values for undoped samples, until 0.03-Ti doped ones. Further Ti addition produces an increase of resistivity with respect to the 0.03 Ti doped samples. Seebeck coefficient does not appreciably change in all the measured temperature range, independently of Ti content. The improvement in electrical resistivity leads to about 55 % higher power factor values for the 0.03 Ti-doped samples than that obtained in the undoped ones. The maximum power factor at 800°C, around 0.33 mW/K 2 m, is slightly higher than the obtained in higher density samples, clearly indicating the good thermoelectric performances of these doped samples.

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“…Micrographs of the samples have been used to analyze the different phases and their distribution. Apparent density measurements have been performed on several samples for each composition after sintering, using 4.677 g/cm 3 as theoretical density [28].…”

Section: Methodsmentioning

confidence: 99%

Doping effect in Ca3Co4−xZnxOy ceramics

Rasekh

Constantinescu

Bosque

et al. 2014

J Mater Sci: Mater Electron

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Ca 3 Co 4-x Zn x O y (x = 0.01, 0.03, and 0.05) polycrystalline thermoelectric ceramics have been prepared by the classical solid state method. XRD data have shown that Ca 3 Co 4 O 9 is the major phase, with small amounts of the Ca 3 Co 2 O 6 one. Moreover, it has been found that the Zn has been incorporated into these two phases. Slight Zn doping decreases electrical resistivity compared with the values obtained in undoped samples. The minimum values have been obtained for the 0.01-Ni doped samples, increasing for further Zn substitution. Seebeck coefficient does not appreciably change in all the measured temperature range, independently of Zn content. The improvement in electrical resistivity leads to higher power factor values for the 0.01 Zn-doped samples (about 30 %) than for the undoped ones. The maximum power factor at 800°C, around 0.27 mW/K 2 m is significantly higher than the best results obtained in Zn doped samples reported in the literature.

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Preparation of high-performance Ca3Co4O9 thermoelectric ceramics produced by a new two-step method

Cited by 82 publications

References 34 publications

Processing effects on the thermoelectric properties of Bi<sub>2</sub>Ca<sub>2</sub>Co<sub>1.7</sub>O<sub>x</sub> ceramics

Processing effects on the thermoelectric properties of Bi<sub>2</sub>Ca<sub>2</sub>Co<sub>1.7</sub>O<sub>x</sub> ceramics

Decrease of electrical resistivity in Ca3Co4O9 thermoelectric ceramics by Ti doping

Doping effect in Ca3Co4−xZnxOy ceramics

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