Studies on thermal decomposition and oxidation of CoSb3

Leszczyński, Juliusz; Wojciechowski, K.; Małecki, Andrzej

doi:10.1007/s10973-011-1461-5

Cited by 59 publications

(28 citation statements)

References 11 publications

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“…At 550°C the oxidation of SKD follow a parabolic rate law in agreement with [9] and [10]; (∆m) 2 = k p t, where ∆m is the change in mass per unit area and k p the parabolic rate constant. The two different stages described in [10] can also be seen with a slight drop in mass between possibly caused by scaling off of the outher oxide layers. The first stage has a slightly higher parabolic rate constant than the second with 5.6 x 10 -6 and 2.1 x 10 -6 kg 2 m -4 h -1 respectively.…”

Section: Methodsmentioning

confidence: 72%

“…At 600°C and 650°C a weight loss is observed. According to [10] an increase in oxidation rate is found at 583°C which could be linked to the phase transition from α-Sb 2 O3 to β-Sb 2 O 3 and subsequent increase in evaporation which would then be faster than the oxidation process resulting in a net mass loss.…”

Section: Methodsmentioning

confidence: 99%

“…For SKD the oxidation and sublimation are well known and have been studied thoroughly over the last decade [6][7][8][9][10][11][12]. Already at 380°C oxidation starts forming a two layer structure of Sb 2 O 3 /Sb 2 O 4 on the outside and CoSb 2 O 4 /CoSb 2 O 6 on the inside.…”

Section: Introductionmentioning

confidence: 99%

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Methods for Enhancing the Thermal Durability of High-Temperature Thermoelectric Materials

Skomedal

Kristiansen

Engvoll

et al. 2013

Journal of Elec Materi

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Thermoelectric materials such as Skutterudites and Magnesium Silicides are being investigated as promising alternatives for medium to high temperature waste heat recovery in the transport sector and industry. A critical success factor for the thermoelectric material is its stability over time when exposed to rapid heating and cooling during its lifetime. In this work the different degradation issues at high temperature are examined for these thermoelectric materials, and several means of enhancing durability have been evaluated. Initial thermal durability studies have been performed with Skutterudites and Magnesium Silicides with candidate coatings for protecting the materials from oxidation and sublimation during thermal cycles in air for up to 500 hours and up to 873K. The samples were then characterized by SEM and EDS. The results showed that it is possible to decrease degradation of the thermoelectric material without compromising the overall thermoelectric efficiency.

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Section: Methodsmentioning

confidence: 72%

Section: Methodsmentioning

confidence: 99%

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Methods for Enhancing the Thermal Durability of High-Temperature Thermoelectric Materials

Skomedal

Kristiansen

Engvoll

et al. 2013

Journal of Elec Materi

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“…Generally, phase stability and resistance to oxidation are the most important factors for evaluating the thermal stability of the filled skutterudites for hightemperature applications. [13][14][15][16][17] The oxidation resistance can be evaluated by using the activation energy for oxidation, and higher activation energies are better for oxidation resistance. In this study, La-filled and Co-substituted skutterudite (La 0.9 Fe 3 CoSb 12 ) was synthesized, and its thermal stability was evaluated.…”

Section: Introductionmentioning

confidence: 99%

Thermal Stability of La0.9Fe3CoSb12 Skutterudite

Shin

Kim

Park

et al. 2014

Journal of Elec Materi

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The thermal stability of the La 0.9 Fe 3 CoSb 12 skutterudite was examined by varying the aging conditions of temperature, time, and atmosphere (air and vacuum). Thermogravimetry, differential scanning calorimetry and x-ray diffraction analyses revealed that the La 0.9 Fe 3 CoSb 12 was significantly oxidized at temperatures above 673 K in air. The Sb-based oxides were preferably formed when aged at high temperatures in air. The thickness of the oxide layers was found to increase with increasing aging temperature and time, while the activation energy for the oxidation of the Fe-Sb-based skutterudite was lower than that of the Co-Sb-based skutterudites. However, when the analysis was performed in a vacuum, the La 0.9 Fe 3 CoSb 12 skutterudite was stable, and no oxide layers were observed after aging at 823 K for 100 h. These results suggest that a protective coating for the skutterudite materials or the encapsulated packaging of the skutterudite modules is required for hightemperature applications.

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“…Oxidation of undoped bulk CoSb 3 exposed to air is reported to start at $644 K and proceed through the formation of various intermediate oxides at high temperatures. 39 The highest temperature involved in the present studies is 700 K. Hence, we consider only cubic a-Sb 2 O 3 (formed at $644 K) and bSb 2 O 3 , which in turn is oxidized to b-Sb 2 O 4 (at $673 K), because the other intermediate oxides are formed at temperatures in excess of 773 K. 39 Depending upon the diffusion of oxygen from the substrate, the antimony oxides can form only in the region near the interface, because the deposition and annealing of the films were done in argon ambient. In an inert ambient, CoSb 3 decomposes into CoSb 2 and elemental Sb only at $773 K. 40 Hence, the formation of CoSb 2 in the bulk of the films can be ruled out.…”

Section: E Oxygen Diffusion and Oxidation Of Cosb 3 At The Interfacementioning

confidence: 99%

Lattice dynamics and substrate-dependent transport properties of (In, Yb)-doped CoSb3 skutterudite thin films

Kumar

Kyu

Alshareef

2011

Journal of Applied Physics

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Lattice dynamics, low-temperature electrical transport, and high-temperature thermoelectric properties of (In, Yb)-doped CoSb3 thin films on different substrates are reported. Pulsed laser deposition under optimized conditions yielded single-phase polycrystalline skutterudite films. Raman spectroscopy studies suggested that In and Yb dopants occupy the cage sites in the skutterudite lattice. Low-temperature electrical transport studies revealed the n-type semiconducting nature of the films with extrinsic and intrinsic conduction mechanisms, in sharp contrast to the degenerate nature reported for identical bulk samples. Calculations yielded a direct bandgap close to 50 meV with no evidence of an indirect gap. The carrier concentration of the films was identical to that reported for the bulk and increased with temperature beyond 250 K. The higher resistivity exhibited is attributed to the enhanced grain boundary scattering in films with a high concentration of grains. The maximum power factor of ∼0.68 W m−1 K−1 obtained at 660 K for the film on glass is found to be nearly four times smaller compared to that reported for the bulk. The observed difference in the power factors of the films on different substrates is explained on the basis of the diffusion of oxygen from the substrates and the formation of highly conducting CoSb2 phase upon the oxidation of CoSb3.

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Studies on thermal decomposition and oxidation of CoSb3

Cited by 59 publications

References 11 publications

Methods for Enhancing the Thermal Durability of High-Temperature Thermoelectric Materials

Methods for Enhancing the Thermal Durability of High-Temperature Thermoelectric Materials

Thermal Stability of La0.9Fe3CoSb12 Skutterudite

Lattice dynamics and substrate-dependent transport properties of (In, Yb)-doped CoSb3 skutterudite thin films

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