GaSb添加和Sb掺杂对Mg_2Si_(0.5)Sn_(0.5)固溶体热电性能的影响(英文)

利用B2O3助熔剂法结合热压法制备了Mg2Si0.487-2x Sn0.5(Ga Sb)x Sb0.013(0.04≤x≤0.10)固溶体。X射线衍射结果表明样品呈单相。Sb掺杂有效提高了样品的电导率。随温度升高,Mg2Si0.487-2x Sn0.5(Ga Sb)x Sb0.013(0.04≤x≤0.10)样品的电导率降低而塞贝克系数升高。随Ga Sb含量的增多,样品的电导率呈现出先增大后减小的变化趋势。所有样品中Mg2Si0.287Sn0.5(Ga Sb)0.1Sb0.013具有最低晶格热导率,其室温晶格热导率比Mg2Si0.5Sn0.5[11]低15%。由于电导率较高使Mg2Si0.327Sn0.5(Ga Sb)0.08Sb0.013具有最高热电优值,在720 K达到0.61,显著高于基体Mg2Si0.5Sn0.5[11]的最高热电优值0.019。     

GaSb添加和Sb掺杂对Mg2Si0.5Sn0.5固溶体热电性能的影响（英文）

利用B2O3助熔剂法结合热压法制备了Mg2Si0.487-2x Sn0.5(Ga Sb)x Sb0.013(0.04≤x≤0.10)固溶体。X射线衍射结果表明样品呈单相。Sb掺杂有效提高了样品的电导率。随温度升高,Mg2Si0.487-2x Sn0.5(Ga Sb)x Sb0.013(0.04≤x≤0.10)样品的电导率降低而塞贝克系数升高。随Ga Sb含量的增多,样品的电导率呈现出先增大后减小的变化趋势。所有样品中Mg2Si0.287Sn0.5(Ga Sb)0.1Sb0.013具有最低晶格热导率,其室温晶格热导率比Mg2Si0.5Sn0.5[11]低15%。由于电导率较高使Mg2Si0.327Sn0.5(Ga Sb)0.08Sb0.013具有最高热电优值,在720 K达到0.61,显著高于基体Mg2Si0.5Sn0.5[11]的最高热电优值0.019。     

Effect of GaSb Addition and Sb Doping on the Thermoelectric Properties of Mg2Si0.5Sn0.5 Solid Solutions

利用B2O3助熔剂法结合热压法制备了Mg2Si0.487-2xSn0.5(GaSb)xSb0.013 (0.04 ≤ x ≤ 0.10)固溶体。X射线衍射结果表明样品呈单相。Sb掺杂有效提高了样品的电导率。随温度升高,Mg2Si0.487-2xSn0.5(GaSb)xSb0.013 (0.04 ≤ x ≤ 0.10)样品的电导率降低而塞贝克系数升高。随GaSb含量的增多,样品的电导率呈现出先增大后减小的变化趋势。所有样品中Mg2Si0.287Sn0.5(GaSb)0.1Sb0.013具有最低晶格热导率,其室温晶格热导率比Mg2Si0.5Sn0.5[11]低15%。由于电导率较高使Mg2Si0.327Sn0.5(GaSb)0.08Sb0.013具有最高热电优值,在720 K达到0.61,显著高于基体Mg2Si0.5Sn0.5[11]的最高热电优值0.019     

四元Mg2Si0.27Ge0.05Sn0.65Sb0.03固溶体的热电性能

通过氧化硼助熔剂法和放电等离子烧结技术制备了Mg_2(1+x)Si_0.27Ge_0.05Sn_0.65Sb_0.03 (x = 0.05, 0.08)四元固溶体热电材料。测量了在300 K - 800 K 的温度区间内测试了所有四元固溶体试样的塞贝克系数、电导率和热导率。研究结果表明随着温度的升高电导率单调降低而塞贝克系数单调升高,所有样品的晶格热导率明显高于通过Abeles模型计算所得到的理论值。最高无量纲热电优值出现在x=0.08样品中,在800 K时达到最高值1.0.     

Ge掺杂Zintl相化合物YbZn2Sb2-xGex的制备及其热电性能

通过熔融反应法结合放电等离子体烧结技术,制备了Ge掺杂的系列样品YbZn2Sb2-xGex(0.0≤x≤0.4)。研究了从300~700 K温度区间的热电输运性能以及低温热容量。结果表明,样品的电导率、Seebeck系数、热导率、ZT值都跟Ge的含量有关。Ge部分取代Sb,提高了体系的空穴载流子浓度,从而降低了电阻率,并且适量的Ge取代能够有效地提高功率因子。Ge的引入,使得样品晶格中原子质量波动增大,加强了对声子的散射,其中x=0.1时,样品YbZn2Sb1.9Ge0.1的热电优值在700 K时达到0.45,比YbZn2Sb2的ZT值高了55%。并且,由ZT-T曲线的趋势判断,其在温度高于700 K时可能具有更高的ZT值。     

新型热电材料β—Zn4Sb3的电学性能

采用真空熔炼和烧结的方法制备了新型热电材料β-Zn4Sb3。X射线衍射分析表明样品为单相。2种样品从室温到723K温度范围内的电学性能测量表明,β-Zn4Sb3在500K～650K时具有较高的功率因子,真空熔炼样品的性能要优于烧结样品,其功率因子在623K时达到最大值3.9μW.cm^-1.k^-2。β-Zn4Sb3在热电转换领域有潜在的应用前景。     

Mg3Sb2材料的自蔓延燃烧合成与热电性能研究

采用自蔓延燃烧合成-等离子活化烧结(SHS-PAS)合成法制备了一系列Mg3+xSb2(0≤x≤0.4)样品,合成了Mg3Sb2单相产物,并研究了自蔓延燃烧过程中Mg过量对本征p型Mg3Sb2材料的晶体结构、热电性能的影响规律,进而确定了通过SHS-PAS方法合成Mg3Sb2的材料化学计量配比的最佳Mg过量量,优化了本...     

N型YbxCo4Sb12热电材料及涂层的制备与性能研究

采用熔融-退火-放电等离子烧结工艺制备了YbxCo4Sb12(x=0.27,0.28,0.29,原子比)合金块体样品.XRD、SEM、EDS分析表明,成功合成了Yb掺杂的单相CoSb3热电材料.当Yb含量从0.27上升至0.29,材料的功率因子随温度的升高呈现先上升后下降趋势,热导率则先下降后上升.由于相对较高的功率因...     

添加Sb的Ga2Te3合金热电性能

本研究采用等摩尔分数的Sb元素替换Ga2Te3中的Ga元素,并利用放电等离子烧结技术制备Ga1.9Sb0.1Te3合金,研究其微观结构和热电性能。结果表明,添加Sb元素后,材料的Seebeck系数为130～240μV/K,明显低于单晶Ga2Te3,电导率为3600～1740??1·m?1,至少是单晶Ga2Te3的17倍,热导率提高近25%。在649K时Ga1.9Sb0.1Te3合金的热电优值(ZT)达到最大值0.1,是同温度下单晶Ga2Te3ZT值的3倍。     

悬浮熔炼制备Half-Heusler合金Zr1-xTixNiSn0.975Sb0.025及其热电性能

采用悬浮熔炼法合成了Zr1-xTixNiSn0.975Sb0.025(x = 0, 0.15, 0.25, 0.5)基Half-Heusler热电材料,X射线衍射结果表明所制备合金为单相.相对于常规方法,悬浮熔炼显著缩短了制备Half-Heusler合金的时间.同时研究了Ti取代及不同热压条件对材料热电性能的影响.结果表明:ZrNiSn0.975Sb0.025合金进行A位取代可降低材料的热导率,而不会明显影响其热电性能.致密度可以影响材料的热电性能,适当的热压条件可以使合金的ZT值达到最大,约为0.45.     

Thermoelectric properties of Sb-doped Mg2Si semiconductors

The thermoelectric properties of Sb-doped Mg₂Si (Mg₂Si:Sb = 1:x(0.001 ≦ x ≦ 0.02)) fabricated by spark plasma sintering have been characterized by Hall effect measurements at 300 K and by measurements of electrical resistivity (ρ), Seebeck coefficient (S), and thermal conductivity (κ) between 300 and 900 K. Sb-doped Mg₂Si samples are n-type in the measured temperature range. The electron concentration of Sb-doped Mg₂Si at 300 K ranges from 2.2 × 10¹⁹ for the Sb concentration, where x = 0.001, to 1.5 × 10²⁰ cm⁻³ for x = 0.02. First-principles calculation revealed that Sb atoms are expected to be primarily located at the Si sites in Mg₂Si. The electrical resistivity, Seebeck coefficient, and thermal conductivity are strongly affected by the Sb concentration. The sample x = 0.02 shows a maximum value of the figure of merit ZT, which is 0.56 at 862 K.     

Thermoelectric properties and electronic structure of p-type Mg2Si and Mg2Si0.6Ge0.4 compounds doped with Ga

Mg₂Si:Ga_x and Mg₂Si_0.6Ge_0.4:Ga_x (x = 0.4% and 0.8%) solid solutions have been synthesized by direct melting in tantalum crucibles and hot pressing. The effect of Ga doping on the thermoelectric properties has also been investigated by measurements of thermopower, electrical resistivity, Hall coefficient and thermal conductivity in temperature range from 300 to 850 K. All samples exhibit a p-type conductivity evidenced by positive sign of both thermopower and Hall coefficient in the investigated temperatures. The maximum value of the dimensionless figure of merit ZT was reached for the Mg₂Si_0.6Ge_0.4:Ga(0.8%) compound at 625 K (ZT ∼ 0.36). The p-type character of thermoelectric behaviours of Ga-doped Mg₂Si and Mg₂Si_0.6Ge_0.4 compounds well corroborates with the results of electronic structure calculations performed by the Korringa-Kohn-Rostoker method and the coherent potential approximation (KKR-CPA), since Ga diluted in Mg₂Si and Mg₂Si_0.6Ge_0.4 (on Si/Ge site) behaves as hole donor due to the Fermi level shifted to the valence band edge. The onset of large peak of DOS from Ga impurity at the valence band edge, well corroborates with high Seebeck coefficient measured in Ga-doped samples.     

含稀土硅化铁热电材料的电学性能初探

采用悬浮真空熔炼和800℃,168h真空退火方法制备了含稀土Sm的FeSi2基金属硅化物,并对其晶体结构、See-beck系数、电阻率进行了初步研究。实验发现,名义组成为Fe0.6Sm0.4Si2的试样的热电功率因子从室温时的0.26×10-4W·m-1K-2随温度上升到500℃时的1.6×10-4W·m-1K-2,比不含Sm或含Sm量很少的对比试样高一个数量级左右。其原因被认为是由于Sm的外层4f电子的贡献。     

Thermoelectric transport properties and structure of Mg2Si0.8Sn0.2 prepared by ECAS under different current intensities

Thermoelectric materials Mg2Si0.8Sn0.2 were sintered under three different conditions including no electricity sintering(NCS), low electricity sintering(LCS),and high electricity sintering(HCS). Thermoelectric performance and microstructure of three group samples were measured and compared. The results indicate that the application of electric current during the sintering process changes the microstructure and significantly increases the density of samples, and increases the electric conductivity and the power factor. The electric current activated/assisted sintering is an effective way to obtain thermoelectric materials with excellent performance.     

热电材料微结构调控热电输运行为的研究进展

热电材料是绿色能源转化、温差电技术应用的关键材料。由于各性能指标相互抑制,材料热电性能改善遇到瓶颈。材料微结构设计协同调控热电性能为下一代热电材料发展提供了一条明确思路。本文介绍热电材料"多尺度微结构构筑"、"电子晶体离子液体"、"晶格缺陷工程"等改善热电性能的新概念,从原子、纳米、微米等尺度分析能带调控、弱键合、非简谐振动效应、纳米畴散射机制、调幅分解、能量过滤机制、相变现象等物理、化学过程对热电输运行为的影响;阐述了热电材料晶体微结构特征,总结了点缺陷、晶界、纳米畴等结构参量对能带结构、载流子自由程、晶格振动模式等物理参量的影响规律;展望了下一代高性能块体热电材料的发展方向。     

Thermoelectric performance of Mg2−xCaxSi compounds

Thermoelectric materials Mg_2−xCa_xSi (x = 0, 0.01, 0.03, 0.05, 0.07, 0.1) compounds have been prepared by vacuum melting followed by hot-pressing. Effects of the substitution of Ca for Mg on phase structures and the thermoelectric properties of the hot-pressed compounds were investigated. It was found that the alloying of Ca in Mg₂Si based compounds increases the electrical conductivity and decreases the Seebeck coefficient of the compounds, due to the electronegativity difference between Ca and Mg. The dimensionless figures of merit of Mg₂Si and Mg_1.99Ca_0.01Si reach, respectively, 0.41 and 0.34 at 660 K.     

Influence of Sb doping on thermoelectric properties of Mg2Ge materials

The Sb-doped Mg₂Ge compounds were successfully synthesized by tantalum-tube weld melting method followed by hot pressing and the thermoelectric properties were examined. The effects of Sb doping on the electrical conductivity, Seebeck coefficient, and thermal conductivity have been investigated in the temperature range of 300–740 K. It was found that the Sb doping with sufficient Mg excess increased the electrical conductivity dramatically, leading to enhancement of the power factors. The thermal conductivity was also reduced upon Sb doping, mainly due to mass fluctuation scattering and strain field effects. Mg_2.2Ge_0.095Sb_0.005 showed a maximum thermoelectric figure of merit of ≈0.2 at 740 K.