Structure and thermoelectric properties of Bi–Te alloys obtained by novel method of oxide substrates reduction

Bochentyn, Beata; Karczewski, Jakub; Miruszewski, Tadeusz; Kusz, B.

doi:10.1016/j.jallcom.2015.06.127

Cited by 15 publications

(6 citation statements)

References 32 publications

(22 reference statements)

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“…Synthesis of porous thermoelectric materials such as Bi 2 Te 3 [27][28][29], (Bi,Sb) 2 Te 3 [29][30][31], Ge 0.77 Ag 0.1 Sb 0.13 Te (TAGS) [32], Bi 2 Te 1-x Se x [33,34] and CsBi 4-Te 6 [35] via this technique has been previously reported. In this method, a mixture of oxides is reduced at a given temperature in a dry hydrogen flow.…”

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confidence: 99%

New synthesis route of highly porous InxCo4Sb12 with strongly reduced thermal conductivity

et al. 2020

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Highly porous, In-filled CoSb 3 skutterudite materials with an attractive thermoelectric figure of merit (ZT * 1) and corresponding dense samples were fabricated through the cost-effective method of reduction in oxides in dry hydrogen and the pulsed electric current sintering (PECS) method, respectively. The reduction process was described in detail using in situ thermogravimetric analysis of Co 2 O 3 , Sb 2 O 3 and In(NO 3) 3 Á5H 2 O separately and in a mixture. Two methods to synthesise the same material were examined: (a) free sintering of an initially reduced powder and (b) PECS. The free-sintered materials with higher porosities (up to * 40%) exhibited lower values of electrical conductivity than the dense PECS samples (porosity up to * 5%), but the benefit of an even sixfold reduction in thermal conductivity resulted in higher ZT values. The theoretical values of thermal conductivity for various effective media models considering randomly oriented spheroid pores are in good agreement with the experimental thermal conductivity data. The assumed distribution and shape of the pores correlated well with the scanning electron microscope analysis of the microstructure. The lowest value of thermal conductivity, equal to 0.5 W/m K, was measured at 523 K for In 0.1 Co 4 Sb 12 with 41% porosity. The highest value of ZT max = 1.0 at 673 K was found for the In 0.2 Co 4 Sb 12 sample in which the porosity was 36%.

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Section: Graphic Abstract Introductionmentioning

confidence: 99%

New synthesis route of highly porous InxCo4Sb12 with strongly reduced thermal conductivity

et al. 2020

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“…Explaining the process of conductivity in oxide glasses may have a key role in understanding the process of reduction in these glasses. Production of new materials based on the reduction process of oxide glasses enjoys great interest in scientific world and still requires further analysis of this phenomenon [19][20][21][22][23]. The investigation may also allow to develop application areas for oxide glasses.…”

Section: Introductionmentioning

confidence: 99%

Determination of ionic conductivity in the Bi-Si-O and Pb-Si-O glasses

Karczewski

Miruszewski

Bochentyn

et al. 2017

Materials Science-Poland

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Impedance spectroscopy measurements in various gas atmospheres were carried out in order to explain the doubts about the type of carriers and the mechanism of electrical conductivity in Bi-Si-O and Pb-Si-O glasses. In bismuth silicate glass, a typical ionic conductivity with oxygen ions as charge carriers was observed. The level of electrical conductivity of the glass at 400 °C was 5 × 10-8 S·cm-1, with the activation energy of 1.3 eV and was independent of measuring atmosphere. In the case of lead silicate glasses, the conductivity changed with measuring atmosphere. Two types of charge carriers: oxygen ions and proton ions were postulated. Proton conductivity measured in wet argon at temperature 400 °C was estimated at the level of 4 × 10-8 S·cm-1 while the oxygen ions conductivity in such conditions was 78 × 10-8 S·cm-1. We suggest that both types of charge carriers are transported along the same conduction paths using oxygen defects in the glass structure.

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“…17 Heat treatment of Bi 2 O 3 -TeO 2 glass powders under H 2 and Ar atmosphere also resulted in the formation of reduced Bi-Te alloys. 18,19 Similarly, an O 2 -deficient environment was found to result in the occurrence of under-coordinated Te, which has a distinct absorption in the UV to visible spectral range. 20 In addition, the formation of Ag nanoparticles in the PbO-GeO 2 -Al 2 O 3 glass during annealing under N 2 at the glass-transition temperature, suggests that the use of N 2 atmosphere has a reducing effect for polyvalent metal ions.…”

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Development of low‐loss lead‐germanate glass for mid‐infrared fiber optics: I. glass preparation optimization

et al. 2020

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Reducing the mid-infrared attenuation loss due to absorption of hydroxyl (OH) groups and scattering of metallic Pb species for lead-germanate glass is essential to pave the way for their applications as low-loss mid-infrared fiber optics. In the first part of this study, we report the understanding of the factors that determine dehydration efficiency and metallic Pb formation during the lead-germanate glassmelting process. Combining a dry O 2-rich atmosphere containing ultra-dry N 2 together with the use of chloride dehydration agent and nitrate oxidation agent compound was found to enable efficient dehydration effect and absence of metallic Pb scattering sources in the dehydrated glasses. This glassmelting procedure overcomes previous limitations on the preparation of similar kinds of heavy-metal oxide glasses, where only pure O 2 atmosphere was used and/or use of fluoride dehydration agent deteriorated the glass thermal stability. This work provides guidance for developing other low-loss mid-infrared glasses/fibers containing multivalent heavy-metal ions such as Pb, Bi, Te, Sb, etc K E Y W O R D S dehydration, lead-germanate glass, metallic Pb, mid-infrared fiber optics, scattering loss Note: The sample ID (ie V#-W#-X#-Y#-Z) include glass composition (type and content of chloride dehydration agent), melting conditions and melting atmospheres, and their detailed definitions are as follows: V: S = no NaCl, no PbCl 2 ; P = with PbCl 2 ; N = with NaCl; with #: molar concentration (mol%) of the dehydration agent, PbCl 2 or NaCl. W = Batch-in-temperature: (A) 650°C; (B) 1250°C; (C) 650°C without chlorides, then added PbCl 2 /NaCl at 1250°C; with # = melting time at 1250°C: (1) 40 min; (2) 80 min; (3) 120 min. X = dry gas type: (O) O 2 ; (ON) O 2 + N 2 ; (N) N 2 ; (A) Ar; with # = dry gas flow rate: (2) 1.6 L/min, (4) 4 L/min, (10) 10 L/min, (16) 16 L/min. Y = N * : use of ultra-dry N 2 ; with # = (1) 35 min, (2) 70 min, (3) 105 min GBP time. Z = O * : release of super-dry O 2 in the glass melt via use of NaNO 3 instead of Na 2 CO 3 in glass batch.

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Structure and thermoelectric properties of Bi–Te alloys obtained by novel method of oxide substrates reduction

Cited by 15 publications

References 32 publications

New synthesis route of highly porous InxCo4Sb12 with strongly reduced thermal conductivity

New synthesis route of highly porous InxCo4Sb12 with strongly reduced thermal conductivity

Determination of ionic conductivity in the Bi-Si-O and Pb-Si-O glasses

Development of low‐loss lead‐germanate glass for mid‐infrared fiber optics: I. glass preparation optimization

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