Thermoelectric Properties of High Density Sintered Ca3Co2O6

2008 ◽  
Vol 54 ◽  
pp. 211-215 ◽  
Author(s):  
Takeo Uesugi ◽  
Hitoshi Kohri ◽  
Ichiro Shiota ◽  
Masahiko Kato ◽  
Isao J. Ohsugi
Keyword(s):  
Solid State ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Hot Pressing ◽  
Temperature Limit ◽  
Thermoelectric Oxide ◽  
Temperature Range ◽  
Seebeck Coefficients ◽  
The One ◽  
Lower Resistivity

Ca3Co4O9 is a promising material for thermoelectric generation, as it is stable up to 1173 K in the air, and shows good thermoelectric properties. Recently, it was found that Ca3Co2O6 was stable up to 1300 K in the air. The Ca3Co2O6 is decomposed phase of Ca3Co4O9 and the temperature limit is higher than one of Ca3Co4O9. The electrical resistivity of Ca3Co2O6 was, however, higher than the one of Ca3Co4O9. Not only high power generation performances but also excellent strength is required for practical use of the thermoelectric oxide materials. Polycrystalline samples of Ca3Co2O6 were prepared by solid-state reaction (SSR) and hot pressing (HP). Relative density of Ca3Co2O6 (HP) was over 98%, which is larger than the one of Ca3Co2O6 (SSR). Ca3Co2O6 (HP) showed larger strength and lower resistivity than Ca3Co2O6 (SSR). The resistivity (ρ) of Ca3Co2O6 (HP) in perpendicular to the pressurized direction decreased from 64 Ωcm to 4.0×10-2 Ωcm at the temperature range between 373 and 1173 K. In addition, the resistivity of this sample was decreased by heat treatment in the air. The Seebeck coefficients (S) of Ca3Co2O6 (HP) was positive value and more than 160 μVK-1 at the temperature range between 373 and 1173 K. Ca3Co1.8M0.2O6 (M= Mn or V) were prepared by solid state reaction and hot pressing. The resistivity of Mn-substituted Ca3Co2O6 (HP-Mn) and V-substituted Ca3Co2O6 (HP-V) were lower than the one of non-substituted Ca3Co2O6 (HP) at the temperature below 523 K for the Mn-substituted sample or 723 K for V-substituted sample. The latter showed the lowest value 1.53 Ωcm of all specimens at 383 K. The power factor (S2ρ-1) of Ca3Co2O6 (HP) was 88.3 μWm-1K-2, which is the largest of all specimens at 1176 K, but S2ρ-1 of V-substituted Ca3Co2O6 (HP-V) is the largest of all specimens up to 773 K.

Ca3Co2O6 for High Temperature Side of Thermoelectric FGM

2009 ◽  
Vol 631-632 ◽  
pp. 489-494
Author(s):  
Takeo Uesugi ◽  
Hitoshi Kohri ◽  
Ichiro Shiota ◽  
Masahiko Kato ◽  
Isao J. Ohsugi
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Thermoelectric Properties ◽  
Thermoelectric Material ◽  
Solid State Reaction ◽  
Hot Pressing ◽  
High Performance ◽  
Waste Heat ◽  
High Temperature Side ◽  
Temperature Range

In modern age, much thermal energy is emitted from ceramic and/or steel industries. Their temperature range is between 500 K and 1300 K. Thermoelectric materials are promising to utilize the waste heat, because of no CO2 emission and long life due to no moving parts. The thermoelectric properties of every thermoelectric material have temperature dependence and high performance appears at a specific temperature range. If the proper materials are placed and joined along the temperature gradient to form an FGM, the performance should be higher than a monolithic material. The performance of a thermoelectric material is expressed by the dimensionless figure of merit ZT=α2ρ-1κ -1T, where α is the Seebeck coefficient, ρ is the electrical resistivity, κ is the thermal conductivity, and T is absolute temperature. Thermoelectric oxides are suitable for high temperature materials because of chemical stability. NaxCoO2 shows relatively high ZT value in thermoelectric oxide at the temperature range below 800 K. Ca3Co4O9 shows ZT ~1 at 1000 K. Recently, it is reported that Ca3Co2O6 that is formed by decomposition of Ca3Co4O9 at 1173 K has high performance at 1300 K. The properties and fabrication condition of high density Ca3Co2O6 are, however, not reported in detail. In order to improve the thermoelectric properties and to shift the temperature range for Ca3Co2O6, we investigated the effects of element substitution. In this experiment, the sintered Ca3Co2-xMxO6 (x=0 or 0.2, M= Mn, Mo or V) were prepared by solid-state reaction or hot pressing. Relative density of Ca3Co2O6 by hot-pressing (HP) was over 94% which is larger than one of Ca3Co2O6 by solid-state reaction (SSR). The resistivity of Mo- or V-substituted Ca3Co2O6 (HP-Mo or HP-V) were lower than one of non-substituted Ca3Co2O6 (HP). The resistivity of Mo-substituted Ca3Co2O6 (HP-Mo) showed the lowest value of 4.3×10-2 Ωcm in all specimens at 1181 K. The power factor α2ρ-1 of Ca3Co2O6 (HP-Mo) was 64.2 Wm-1K-2, which is the largest of all specimens at 1178 K, and this value is approximately 1.3 times higher than 48.8 Wm-1K-2 for Ca3Co2O6 (HP).

Influence of R3+ ion sizes on the thermoelectric properties of RBaCo4O7+δ ceramics

2015 ◽  
Vol 29 (26) ◽  
pp. 1550154 ◽  
Author(s):  
F. Gao ◽  
Q. L. He ◽  
F. Wu ◽  
D. L. Yang ◽  
X. Hu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Solid State ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Oxygen Adsorption ◽  
Reaction Method ◽  
Transition Phenomenon ◽  
Seebeck Coefficients

The influence of [Formula: see text] ion sizes on the electrical resistivity, Seebeck coefficients, thermal conductivity and [Formula: see text] values of [Formula: see text] prepared by the solid-state reaction method was investigated from 373 K to 973 K. The electrical resistivity decreases with decreasing [Formula: see text] ion sizes. Both the electrical resistivity and the Seebeck coefficients have a transition at about 630 K. Especially, the transition phenomenon disappears gradually with decreasing [Formula: see text] ion sizes, and is attributed to the oxygen adsorption of [Formula: see text]. The [Formula: see text] values increase with rising temperature or decreasing [Formula: see text] ion sizes. The [Formula: see text] with the smallest [Formula: see text] size has the maximum [Formula: see text] value that reaches 0.1 at 973 K.

High-Temperature Thermoelectric Properties of Pb- and La-Substituted Bi2Sr2Co2Oy Misfit Compounds

2010 ◽  
Vol 105-106 ◽  
pp. 336-338 ◽  
Author(s):  
Hao Shan Hao ◽  
Jin Qin Ye ◽  
Yong Tao Liu ◽  
Xing Hu
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Thermoelectric Performance ◽  
Simultaneous Increase ◽  
Reaction Method ◽  
Seebeck Coefficients

Pb- and La-substituted (Bi,Pb)2(Sr,La)2Co2Oy samples were prepared by solid-state reaction method and the effect of element substitution on the high-temperature thermoelectric properties was investigated. It was found that the presence of Pb and La elements improved the thermoelectric properties of the Bi2Sr2Co2Oy system owing to the simultaneous increase of conductivity and Seebeck coefficients. The optimal thermoelectric performance was obtained in Pb and La co-substituted samples and the power factor could reach 2.1×10-4Wm-1K-2 at 1000K.

scholarly journals Synthesis and thermoelectric properties of Ce(Ru0.67Rh0.33)4Sb12.

2003 ◽  
Vol 793 ◽  
Author(s):  
Geoff D. Staneff ◽  
Paul D. Asimow ◽  
Thierry Caillat
Keyword(s):  
Solid State ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Temperature Limit ◽  
Nominal Composition ◽  
Charge Balance ◽  
Filled Skutterudite ◽  
Synthesis Routes ◽  
Carrier Charge ◽  
P Type

ABSTRACTExotic filled skutterudite compositions show promise for thermoelectric applications. Current work was undertaken with a nominal composition of Ce(Ru0.67Rh0.33)4Sb12 to experimentally verify its potential as an n-type thermoelectric material. Nominal electroneutrality was expected at 0.89 cerium filling and fully filled materials were expected to be strongly n-type. Filled precursors of the nominal composition were synthesized using straightforward solid state reaction techniques, but standard synthesis routes failed to produce a fully-filled homogenous phase. Instead, the filled thermoelectric Ce(Ru0.67Rh0.33)4Sb12 was synthesized using a combination of solid state reaction of elemental constituents and high pressure hot pressing. A range of pressure-temperature conditions was explored; the upper temperature limit of filled skutterudite in this system decreases with increasing pressure and disappears by 12 GPa. The optimal synthesis was performed in multi-anvil devices at 4–6 GPa pressure and dwell temperatures of 350–700 °C. rutheniumThe result of this work, a Ce(Ru0.67Rh0.33)4Sb12 fully filled skutterudite material, exhibited unexpected p-type conductivity and an electrical resistance of 1.755 mΩ-cm that increased with temperature. Thermal conductivity, Seebeck coefficient, and resistivity were measured on single phase samples. In this paper, we report the details of the synthesis routeand measured thermoelectric properties, speculate on the deviation from expected carrier charge balance, and discuss implications for other filled skutterudite systems.

scholarly journals Thermoelectric Properties of MnSi1.74-1.75:Gem Prepared by Solid-State Reaction and Hot Pressing

2019 ◽  
Vol 57 (4) ◽  
pp. 264-269
Author(s):  
In-Jae Lee ◽  
Sol-Bin Park ◽  
Soon-Chul Ur ◽  
Kyung-Wook Jang ◽  
Il-Ho Kim
Keyword(s):  
Solid State ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Hot Pressing

scholarly journals Thermoelectric properties of Cu3SbSe3 with intrinsically ultralow lattice thermal conductivity

2014 ◽  
Vol 2 (38) ◽  
pp. 15829-15835 ◽  
Author(s):  
Kriti Tyagi ◽  
Bhasker Gahtori ◽  
Sivaiah Bathula ◽  
A. K. Srivastava ◽  
A. K. Shukla ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid State ◽  
Spark Plasma Sintering ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Electrical Transport ◽  
Single Phase ◽  
Lattice Thermal Conductivity ◽  
Plasma Sintering ◽  
Spark Plasma

Intrinsically ultra-low thermal conductivity and electrical transport in single-phase Cu2SbSe3 synthesized employing a solid state reaction and spark plasma sintering.

Thermoelectric properties of Sb-doped tin oxide by a one-step solid-state reaction

2021 ◽  
Author(s):  
Leilane R. Macario ◽  
Andrew Golabek ◽  
Holger Kleinke ◽  
Edson R. Leite
Keyword(s):  
Solid State ◽  
Thermoelectric Properties ◽  
Tin Oxide ◽  
Solid State Reaction ◽  
One Step

Thermoelectric Properties Enhancement of NaCo2O4 through Ca Atom Partial Substitution on Na Atom

2015 ◽  
Vol 1123 ◽  
pp. 140-144 ◽  
Author(s):  
Erwin Ermawan ◽  
Suhardjo Poertadji
Keyword(s):  
Solid State ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Single Phase ◽  
Substitution Effect ◽  
Charge Carriers ◽  
Reaction Process ◽  
Partial Substitution ◽  
Positive Sign ◽  
Power Properties

Single phase samples of Na1-xCaxCo2O4 (with x = 0, 0.1, 0.2 and 0.3) are prepared by utilizing a solid state reaction process, and the Ca2+ substitution effect on thermoelectric properties is then observed. On the samples, the increment of Ca2+ substitution results in the increase of resistivity and thermo power properties. The Ca2+ substitution in NaCo2O4 reduces charge carriers of the samples. This phenomenon indicates that there are many holes in the samples and it is consistent with the positive sign of thermo power. It demonstrates that the Ca2+ substitution is effective to enhance thermoelectric properties.

Study of Thermal Oxide Solid-State Reaction on GaAs Surfaces

1991 ◽  
Vol 238 ◽  
Author(s):  
Z. Lu ◽  
D. Chen ◽  
R. M. Osgood ◽  
D. V. Podlesnik
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Photoelectron Spectroscopy ◽  
Interface Reaction ◽  
Decomposition Reaction ◽  
Thermal Reaction ◽  
Native Oxide ◽  
X Ray ◽  
Temperature Range ◽  
Thermal Oxide

ABSTRACTIn this paper, we will present a study of the thermal reaction of AsjOs with GaAs at temperatures below 550°C using monochromatic X-ray photoelectron spectroscopy (MXPS). A solid-state interface reaction of 4GaAs + 3AS2O5 → 2Ga2O3 + 3AS2O3 + 4As, which includes the usual native oxide thermal reaction: 2GaAs + AS2O3 → Ga2O3 + 4As, as well as a decomposition reaction AS2O5 → AS2O3 + O2 is responsible for the thermal reaction in this temperature range.

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