Effect of Ca substitution by Fe on the thermoelectric properties of Ca3Co4O9 ceramics - Archive ouverte HAL Access content directly
Journal Articles Journal of Electroceramics Year : 2018

## Effect of Ca substitution by Fe on the thermoelectric properties of Ca3Co4O9 ceramics

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Fabian Delorme
• Function : Correspondent author
Fabien Giovannelli

#### Abstract

(Ca$_{1-x}$Fe$_x$)$_3$Co$_4$O$_9$ polycrystalline samples (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.1 and 0.2) have been prepared by solid state reaction and sintered by spark plasma sintering. Their thermoelectric properties have been studied between 323 and 1000 K. The substitution limit is low (< 3%). For higher iron contents, formation of Co$_3$O$_4$, Ca$_2$FeCoO$_5$ and a calcium ferrite compound occurs. Concerning electrical conductivity and power factor, an optimum value exists for x = 0.03 substitution. This optimum power factor is circa 10% higher than the one of the unsubstituted sample. The optimum thermal diffusivity is measured for the sample with x = 0.02 and is circa 9% lower than the one of the unsubstituted sample. Therefore, the dimensionless figure of merit ZT is finally increased by 14% for the (Ca$_{0.98}$Fe$_{0.02}$)$_3$Co$_4$O$_9$ and (Ca$_{0.97}$Fe$_{0.03}$)$_3$Co$_4$O$_9$ compositions.

#### Domains

Engineering Sciences [physics] Materials

### Dates and versions

hal-01741366 , version 1 (23-03-2018)

### Identifiers

• HAL Id : hal-01741366 , version 1
• DOI :

### Cite

Fabian Delorme, P. Diaz-Chao, Fabien Giovannelli. Effect of Ca substitution by Fe on the thermoelectric properties of Ca3Co4O9 ceramics. Journal of Electroceramics, 2018, 40 (2), pp.107 - 114. ⟨10.1007/s10832-018-0109-2⟩. ⟨hal-01741366⟩

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