Effect of reducing annealing on the microstructure and thermoelectric properties of La–Bi co-doped SrTiO3 ceramics

Gong, Chunlin; Dong, Gaogao; Hu, Jiaxin; Chen, Yongsheng; Qin, Mengjie; Yang, Song; Gao, Feng

doi:10.1007/s10854-017-7361-0

Cited by 16 publications

(11 citation statements)

References 22 publications

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“…The small variation in electrical conductivity up to maximum temperature suggested that the oxygen content did not significantly change even though we expect this to play an important part [14]. At high temperature, the electrical conductivity decreased slightly due to the intensified thermal vibration of crystal lattice which enhanced the scattering effect and reduced the carrier mobility [15][16]. The release of weakly bonded oxygen inducing oxygen deficiency on the family of layered perovskite related oxides may also played a part in the reduction of carrier concentration, hence further decreasing the conductivity [16][17][18].…”

Section: Resultsmentioning

confidence: 99%

Effect of annealing temperature on thermoelectric properties of YBa₂Cu₃O_7-xceramic

Wannasut

Yawirach

Boonsong

et al. 2023

J. Phys.: Conf. Ser.

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We have studied the effect of annealing temperature on oxygen content and thermoelectric properties of YBa2Cu3O7-x (YBCO) ceramics fabricated by hot-pressing method. The as-calcined powder was subjected to the applied pressure of 70 MPa at 800 °C for 1 h under Ar atmosphere. The YBCO ceramics were then annealed at 700 and 750 °C for 4 h in oxygen atmosphere. The XRD results showed that all samples possessed pure orthorhombic YBCO phase. The annealing process seemed to induce the reduction of the electrical conductivity and metallic-to-semiconducting transition when the annealing temperature was increased. The temperature dependence of ZT showed a close relation to that of electrical conductivity, suggesting the dominant role of the charged carriers present in these samples.

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Section: Resultsmentioning

confidence: 99%

Effect of annealing temperature on thermoelectric properties of YBa₂Cu₃O_7-xceramic

Wannasut

Yawirach

Boonsong

et al. 2023

J. Phys.: Conf. Ser.

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“…As the figure shows, the obtained ZT values were mainly in the range of 0.1–0.4, representing some of the best values ever reported. Some of the ZT values ( ZT > 0.35) are summarized in Table . ,− In each reference, the selected TE parameters occurred at the same temperature as the best ZT value. In these studies, reduction atmosphere sintering (5 or 10% H 2 ) was commonly used to boost the electrical conductivity of the materials.…”

Section: Resultsmentioning

confidence: 99%

Enhancement of Thermoelectric Performance of Sr_0.9La_0.1TiO₃-Based Ceramics Regulated by Nanostructures

Qin

Lou

Zhang

et al. 2020

ACS Appl. Mater. Interfaces

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La-doped strontium titanite (Sr 0.9 La 0.1 TiO 3 ) is a promising candidate for n-type oxide thermoelectric materials. However, the ZT values of this material are low, leading to low conversion efficiency. Improvements in this efficiency are required. In this work, a high ZT value of 0.50 was obtained for Sr 0.9 La 0.1 TiO 3 ceramic samples by adding 10 wt % Bi 2 O 3 sintering aids and 20 wt % nanosized Ti powders to the matrix material. Although Ti was oxidized to TiO 2 during the sintering process, nanoscale phase interfaces were beneficial for phonon scattering and thermal conductivity reduction. Nanosized metallic Bi and Bi 2 O 3 particles were observed. These two factors played an important role in reducing the thermal conductivity from 2.5 W/(m K) at room temperature to 1.31 W/(m K) at 1073 K. Nanostructure control using nanosized metal powders as additives combined with the Bi 2 O 3 sintering aid paves a way for enhancement of thermoelectric properties of oxide thermoelectric materials.

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“…La‐doped SrTiO 3 ceramic samples (Sr 0.9 La 0.1 TiO 3 ) incorporated with 20 wt% nano‐Ti particles and a small amount of Bi 2 O 3 as a sintering agent, denoted as “SLTB/20Ti”, were prepared by conventional solid state reaction method. Detailed synthesis procedures were reported elsewhere . The SLTB/20Ti bulk material was sintered in argon atmosphere for 2 h at 1450 °C and then cut into rectangular bars with a dimension of 15 mm×4 mm×3 mm for annealing.…”

Section: Methodsmentioning

confidence: 99%

“…ZT values for the samples increased with increasing temperature, and the samples had ZT values of 0.15

<

<

0.65 at 450–1100 K. Gong et al . annealed fully densified La‐doped SrTiO 3 ceramics that were placed beside graphite powder under a flow of Argon gas . An annealing process was taken at 1450 °C for 16 h, and the ZT values varied from 0.09 to 0.27 as the temperature increased from 460 K to 1100 K.…”

Section: Introductionmentioning

confidence: 99%

Annealing of Strontium Titanate Based Thermoelectric Materials by Graphite: Mechanistic Analysis by Spectroscopic and Chromatographic Techniques

Lee

Qin

et al. 2020

ChemPlusChem

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Strontium titanate (SrTiO 3 ) based materials are promising for high-temperature thermoelectric applications. In order to enhance their performance, annealing is usually required and carried out under various atmospheres. Annealing with graphite is quite effective, but the mechanism is not yet clear. In this work, we use IR spectroscopy and gas chromatography (GC) to monitor the chemical environment under the annealing conditions (1350°C for 8 h under 16.9 mL/min N 2 with graphite) and quantify the various gases evolved in the process. It is shown that reducing agents, H 2 and CO (concentrations peaked at ca. 0.4-0.5 %), are generated from graphite in the annealing process. H 2 is produced in carbon gasification reaction, which also generates CO. Additional CO is produced from incomplete combustion of carbon. In the annealing of a La-doped SrTiO 3based ceramic with graphite, higher levels of H 2 O and CO 2 are detected, which is resulted from the reduction of the ceramic by H 2 and CO, respectively. About 67 % of the oxygen vacancies were created by CO reduction while about 33 % by H 2 reduction. The conclusions are well supported by direct weight loss measurements with a difference of less than 6 %.[a] Dr.

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Effect of reducing annealing on the microstructure and thermoelectric properties of La–Bi co-doped SrTiO3 ceramics

Cited by 16 publications

References 22 publications

Effect of annealing temperature on thermoelectric properties of YBa₂Cu₃O_7-xceramic

Effect of annealing temperature on thermoelectric properties of YBa₂Cu₃O_7-xceramic

Enhancement of Thermoelectric Performance of Sr_0.9La_0.1TiO₃-Based Ceramics Regulated by Nanostructures

Annealing of Strontium Titanate Based Thermoelectric Materials by Graphite: Mechanistic Analysis by Spectroscopic and Chromatographic Techniques

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Effect of reducing annealing on the microstructure and thermoelectric properties of La–Bi co-doped SrTiO3 ceramics

Cited by 16 publications

References 22 publications

Effect of annealing temperature on thermoelectric properties of YBa2Cu3O7-xceramic

Effect of annealing temperature on thermoelectric properties of YBa2Cu3O7-xceramic

Enhancement of Thermoelectric Performance of Sr0.9La0.1TiO3-Based Ceramics Regulated by Nanostructures

Annealing of Strontium Titanate Based Thermoelectric Materials by Graphite: Mechanistic Analysis by Spectroscopic and Chromatographic Techniques

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Effect of annealing temperature on thermoelectric properties of YBa₂Cu₃O_7-xceramic

Effect of annealing temperature on thermoelectric properties of YBa₂Cu₃O_7-xceramic

Enhancement of Thermoelectric Performance of Sr_0.9La_0.1TiO₃-Based Ceramics Regulated by Nanostructures