Ag-Bi-Sb-Te四元合金的热电性能

以Ag、Bi、Sb、Te为原料在1373K真空熔炼合成了AgxBi0.5Sb1.5-xTe3(x=0～0.5)合金.微观组织和结构分析显示,真空熔炼的合金具有层状组织特征,属R3m晶体结构,当x≥0.2时出现面心立方AgSbTe2相.电学性能测试表明,在300～580K温度范围内合金的电导率随温度升高而下降,掺Ag后合金的电导率明显提高,掺Ag量为x=0.1试样的最大值达到2.3×105S/m.材料的Seebeck系数均为正值,表明掺Ag合金为p型半导体.     

Thermoelectric properties of p-type PbTe-PbSe alloys

The thermoelectric properties of p-type PbTe-PbSe alloys have been studied as a function of temperature. The high-temperature figures of merit of several alloy compositions have been found to be significantly greater than PbTe. This improvement is related to the ability to achieve higher doping levels in these alloys and, hence, superior electrical properties at elevated temperatures.     

水热合成Bi-Te-Se合金及其热电性能

用水热法在473K下反应24h,制备了Bi-Te-Se三元合金.其粉末产物由结构相同成份接近的两相Bi-Te-Se合金组成.粉末在523K,50MPa压力下热压成的块材也是两相结构.粉末和块体材料的微观形貌均由层片状颗粒组成,层片厚度为100nm左右.通过改变Te的相对含量,可以调节施主掺杂浓度.材料具有很低的热导率,在349K时试样Bi2Te2.85Se0.45具有晶格热导率最低值为0.33W/m·K.此时,它也具有最高的ZT值为0.60.     

Thermoelectric properties of Cu-added Zn–Sb based alloys with multi-phase equilibrium

The polycrystalline samples of Cu-added Zn–Sb based alloys with multi-phase equilibrium were prepared by spark plasma sintering and their microstructures and thermoelectric properties were evaluated. After Cu addition into Zn–Sb based alloys we observed a major phase ZnSb, β-Zn₄Sb₃, the second phase Cu₂Sb and remnant Zn. The ZnSb phase plays an important role in increasing Seebeck coefficient (α) and decreasing electrical conductivity (σ), and Cu₂Sb is of significance to the improvement of the thermoelectric performance. The thermal conductivities (κ) increase with Cu content, and are almost independent of temperature below 574 K. If in comparison with the highest ZT value (ZT = 0.48, at 654 K) of Zn₄Sb₃ prepared in the present work, we obtain the value of 0.7 for the alloy with a certain Cu concentration at the corresponding temperature.     

Thermoelectric behaviour of amorphous magnetic alloys

The Thermoelectric emfs of thermocouples formed by amorphous METGLAS 2826 (Fe₄₀Ni₄₀P₁₄B₆) and METGLAS 2826B (Fe₂₉Ni₄₉P₁₄B₆Si₂) with standard thermocouple wires like copper, chromel, alumel, etc., were measured as a function of temperature between −196° C and 30° C to assess their suitability as thermoelectric temperature sensors. Thermoelectric emfs generated by METGLAS 2826/Cu and METGLAS 2826B/Cu thermocouples at −196° C are about an order of magnitude smaller when compared to thermal emfs of a standard copper/constantan thermocouple at the same temperature.     

Thermoelectric power of palladium-iron alloys at Millikelvin temperatures

The thermoelectric powerS of a pure palladium sample and four alloys ofPdFe, containing 77–400 ppm Fe, has been measured at temperatures down to 5 mK. A sign change inS is observed at low temperatures in all of the alloys, consistent with the onset of spin-glass freezing, the crossover temperature varying as the square of Fe concentration. We also observed that these alloys could be used as useful secondary thermometers down to at least 5 mK.SRC Senior Visiting Fellow 1980, on leave from Michigan State University, Michigan.     

SPS法制备Bi_2Te_3基热电合金的热电性能

用粉末冶金工艺结合SPS烧结制备了p型(Bi0.2Sb0.8)2Te3和n型Bi2(Te0.975Se0.025)3多晶半导体合金,研究烧结工艺对其热电性能的影响.结果表明,室温下,p型(Bi0.2Sb0.8)2Te3材料的热电优值Z为3.25×10<'-3K<'-1,n型Bi2(Te0.975Se0.025)3材料的热电优值Z为2.21×10<'-3K<'-1.     

Thermoelectric properties of ultradisperse materials

Formulas for estimating thermoelectric properties in ultradisperse materials are obtained. The possibility of increasing the thermoelectric efficiency is analyzed.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 39, No. 6, pp. 1035–1038, December, 1980.     

Thermoelectric properties of ZnO-based materials

Abstracts are not published in this journal     

Thermoelectric properties of (Bi0.25Sb0.75)2Te3 alloys fabricated by hot-pressing method

Thermoelectric properties of the hot-pressed p-type (Bi_0.25Sb_0.75)₂Te₃ alloy were characterized with variation of the hot-pressing temperature and the starting powder size. The roles of the factors which affect the Seebeck coefficient of the hot-pressed (Bi_0.25Sb_0.75)₂Te₃ alloy has been elucidated in this study. The donor-like behavior of oxygen could be one of the possible explanations for the higher Seebeck coefficient of the hot-pressed (Bi_0.25Sb_0.75)₂Te₃ alloy. Te vacancies formed by mechanical deformation during the powdering process significantly promote the diffusion of second phase Te atoms into their lattice sites so that the matrix Te solubility approaches its equilibrium value at a given temperature in a relatively short length of time. Using the Seebeck coefficient at various hot-pressing temperatures, the micro-phase diagram near the stoichiometric composition of (Bi_0.25Sb_0.75)₂Te₃ was evaluated.     

Thermoelectric properties of screen-printed ZnSb film

The thermoelectric properties of ZnSb thin film prepared by screen printing technique are investigated, aiming to achieve a low-cost and eco-friendly thermoelectric power generator module. The printed ZnSb thin film, annealed at 580 °C in a furnace tube achieves a power factor of 1.06 mW/mK² and a Seebeck coefficient of 109 μV/K. The output power density is 0.22 mW/cm² at ΔT = 70 K. The feasibility of a flexible thermoelectric module using the screen printing technique is also demonstrated.     

Thermoelectric properties of p-type PbSe nanowires

The thermoelectric properties of individual solution-phase synthesized p-type PbSe nanowires have been examined. The nanowires showed near degenerately doped charge carrier concentrations. Compared to the bulk, the PbSe nanowires exhibited a similar Seebeck coefficient and a significant reduction in thermal conductivity in the temperature range 20 K to 300 K. Thermal annealing of the PbSe nanowires allowed their thermoelectric properties to be controllably tuned by increasing their carrier concentration or hole mobility. After optimal annealing, single PbSe nanowires exhibited a thermoelectric figure of merit (ZT) of 0.12 at room temperature.      

Thermoelectric stability of thermocouples made of high-melting metals or their alloys

Conclusions It is advisable to keep in mind the possible variation of the thermocouple calibration characteristics at high temperatures. A certain stabilization of these characteristics can be obtained by a preliminary annealing of thermocouples at temperatures higher than their operating temperatures.     

Thermoelectric properties of vapor-grown polycrystalline cubic SiC

Polycrystalline cubic silicon carbide layers, undoped and codoped with nitrogen and boron, have been grown via thermal decomposition of methyltrichlorosilane vapor in hydrogen, and their transport properties (electrical conductivity, thermoelectric power, and thermal conductivity) have been studied in the temperature range 80–1100 K.