Thermoelectric Ca3Co4O9 ceramics consolidated by Spark Plasma sintering

Abstract

Hole-doped Ca 3 Co 4 O 9 (Co349) ceramics were prepared using solid-state reaction. Two processing strategies have been used to produce the thermoelectric oxide ceramics, Conventional and Spark Plasma (SPS) Sintering to control the grains consolidation, texturation and sample densification. Thermoelectric properties were measured and the influence of the processing conditions on the properties was evidenced. SPS favours shorter elaboration times and produces samples with larger thermoelectric properties due to better densification and alignment. The effect of the free deformation and texturation using the SPS technique is discussed. Seebeck coefficient values of 180 μV/K at 873 K are obtained.

High-temperature thermoelectric properties of late rare earth-doped Ca3Co4O9+δ

“…As a result, we find that the magnitude of ZT for the Ca 2. 8 ple attains 0.36 at 1073 K, which seems to be the most significant improvement as compared to Bi-, Sr-, Na-, Nd-, Gd-, Eu-, Y-, Gd/Yand Yb-doped samples.…”

“…However, practical application for power generation using waste heat is quite limited due to the Na volatility and poor resistance to humidity for NaCo 2 O 4 . Another Co-based oxide Ca 3 Co 4 O 9+ı has been intensively investigated due to its thermal and chemical stabilities at high-temperature in air [3][4][5][6][7][8][9] along with good thermoelectric performance e.g., ZT = 0.83 at 973 K for the single crystal [3]. [4].…”

Texture, mechanical and thermoelectric properties of Ca3Co4O9 ceramics

“…An alternative way is to use polycrystalline materials by optimising their elaboration process. Hot-pressing (HP) and spark plasma sintering (SPS) processings have been reported [10,11] to allow elaboration of 349 ceramics with high textures and/or strong bulk density, both improving significantly their TE performances.…”

Thermoelectric performance of textured Ca3−xYbxCo4O9−δ ceramics

“…For instances, by combining special post-treatment method, such as spark plasma sintering, sinter-forging, hot pressing, magnetic field and thermo-forging methods, the properties of Ca 3 Co 4 O 9−ı could be improved though adjusting the dense and textured state of polycrystalline oxide [8][9][10]. In addition, because of the special lamellar structure of Ca 3 Co 4 O 9−ı , the carrier concentration and mobility are important factors on electrical properties.…”