Effect of fabrication conditions on microstructure and thermoelectric properties of the Bi1.9Lu0.lTe3 compound was studied. Starting nanopowder with mean nanoparticle size of -37 nm was synthesized by a microwave-solv...Effect of fabrication conditions on microstructure and thermoelectric properties of the Bi1.9Lu0.lTe3 compound was studied. Starting nanopowder with mean nanoparticle size of -37 nm was synthesized by a microwave-solvothermal method. In order to prepare samples with various micro-grained structures, the synthesized nanopowder was compacted by two methods. The first method is cold isostatic pressing with further high- temperature annealing, while the second method is spark plasma sintering at various temperatures of process （653 and 683 K）. It is found that mean grain size is equal to -290,-730 and -1160 nm for cold isostatically pressed and spark plasma sintered at 653 and 683 K samples, respectively. The micro-grained sample with maximum mean grain size shows the best thermoelectric properties. This sample is structurally inhomogeneous and has the lowest thermal conductivity and the specific electrical resistivity. Maximum dimensionless figure of merit for this sample is equal to -0.9 for temperature range of 450-500 K.展开更多
Last two decades have witnessed significant progress in thermoelectric research, to which materials processing has crucial contributions. Compared with traditional zone-melting method used for fabricating bismuth tell...Last two decades have witnessed significant progress in thermoelectric research, to which materials processing has crucial contributions. Compared with traditional zone-melting method used for fabricating bismuth telluride alloys, new powder-based processes have more freedom for manipulating nanostructnres and nanocomposites. Thermoelectric performance enhancement is realized in most thermoelectric materials by introducing fine-grained and nano-composite structures with accurately controlled compositions. This review gives a comprehensive summary on the processing aspects of thermoelectric materials with three focuses on the powder synthesis, advanced sintering process and the formation of nanostructures in bulk materials.展开更多
A typical approach involving Pechini method and spark plasma sintering （SPS） method was presented for the preparation of high density Li5＋xSrxLa3_xBi2012 （x = 0, 1） ceramics. Phase formation, microstructure, grai...A typical approach involving Pechini method and spark plasma sintering （SPS） method was presented for the preparation of high density Li5＋xSrxLa3_xBi2012 （x = 0, 1） ceramics. Phase formation, microstructure, grain size and electrical properties of the specimens were examined using XRD, SEM and alternating current impedance spectro- scopy （ACIS）. Dense LisLa3Bi2012 and LisSrLa2Bi2012 ceramics with pure garnet-like phase, relative density of 97% and average grain size of about 5 pm were fabricated using this approach. The total conductivities at 298 K of Li5La3Bi2012 and LisSrLa2Bi2O12 ceramics prepared by the SPS method are 5.1 Qian-Feng FANG105 and 6.810SS/cm, respectively, 2 times higher than that of samples prepared by the conventional sintering method.展开更多
基金financially supported by the Ministry of Education and Science of the Russian Federation (No.3.6586.2017/BY and 03.G25.31.0246)
文摘Effect of fabrication conditions on microstructure and thermoelectric properties of the Bi1.9Lu0.lTe3 compound was studied. Starting nanopowder with mean nanoparticle size of -37 nm was synthesized by a microwave-solvothermal method. In order to prepare samples with various micro-grained structures, the synthesized nanopowder was compacted by two methods. The first method is cold isostatic pressing with further high- temperature annealing, while the second method is spark plasma sintering at various temperatures of process （653 and 683 K）. It is found that mean grain size is equal to -290,-730 and -1160 nm for cold isostatically pressed and spark plasma sintered at 653 and 683 K samples, respectively. The micro-grained sample with maximum mean grain size shows the best thermoelectric properties. This sample is structurally inhomogeneous and has the lowest thermal conductivity and the specific electrical resistivity. Maximum dimensionless figure of merit for this sample is equal to -0.9 for temperature range of 450-500 K.
基金supported by the National Natural Science Foundation of China(Grant No.11474176)the Ministry of Science and Technology of China(Grant No.2013CB632503)
文摘Last two decades have witnessed significant progress in thermoelectric research, to which materials processing has crucial contributions. Compared with traditional zone-melting method used for fabricating bismuth telluride alloys, new powder-based processes have more freedom for manipulating nanostructnres and nanocomposites. Thermoelectric performance enhancement is realized in most thermoelectric materials by introducing fine-grained and nano-composite structures with accurately controlled compositions. This review gives a comprehensive summary on the processing aspects of thermoelectric materials with three focuses on the powder synthesis, advanced sintering process and the formation of nanostructures in bulk materials.
文摘A typical approach involving Pechini method and spark plasma sintering （SPS） method was presented for the preparation of high density Li5＋xSrxLa3_xBi2012 （x = 0, 1） ceramics. Phase formation, microstructure, grain size and electrical properties of the specimens were examined using XRD, SEM and alternating current impedance spectro- scopy （ACIS）. Dense LisLa3Bi2012 and LisSrLa2Bi2012 ceramics with pure garnet-like phase, relative density of 97% and average grain size of about 5 pm were fabricated using this approach. The total conductivities at 298 K of Li5La3Bi2012 and LisSrLa2Bi2O12 ceramics prepared by the SPS method are 5.1 Qian-Feng FANG105 and 6.810SS/cm, respectively, 2 times higher than that of samples prepared by the conventional sintering method.
