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<p>FeNb<sub>1-<i>x</i></sub>Hf<sub><i>x</i></sub>Sb (<i>x</i> = 0.0, 0.10, 0.20) alloys were synthesized by successive induction melting and mechanical alloying (MA). Mass fluctuations followed by disorder scattering were present due to the difference in mass and size between Hf and Nb atoms. Disorder scattering largely affected the thermoelectric properties. Thermoelectric properties were investigated against temperatures from 300 to 800&#xa0;K. The electrical conductivities of the parent FeNbSb alloy and the slightly doped FeNb<sub>0.9</sub>Hf<sub>0.1</sub>Sb samples exhibited semiconducting trends with smaller conductivity values over the entire temperature range. In contrast, the most doped FeNb<sub>0.8</sub>Hf<sub>0.2</sub>Sb sample showed a metal-like behavior. The metallic trend indicates that typical acoustic phonon scattering dominates the charge transfer. Seebeck coefficients increase remarkably with the temperature increasing due to Hf-doping at the studied doping range due to the remarkable effect of Hf-doping on the carrier concentration. The highest recorded power factor was obtained at 20&#xa0;µWcm<sup>−1</sup>&#xa0;K<sup>−2</sup> for the highest Hf-doped FeNb<sub>0.8</sub>Ti<sub>0.2</sub>Sb alloy. The enhanced point-defect and electron–phonon scatterings remarkably contributed to a reduction in the lattice thermal conductivity and consequently improved thermoelectric figure of merit. The maximum figure of merit (<i>zT</i>) was observed for the same sample with a value of 0.17, recorded at 700&#xa0;K.</p>

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Thermoelectric Investigations of FeNb1-xHfxSb Half-Heusler Alloys

  • 期刊论文

  • 发表日期：

    2025年12月25日

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  • A. M. Adam,
  • A. K. Diab,
  • T. Lychagina,
  • D. Nikolayev,
  • V. Khovaylo,
  • E. M. Elsehly,
  • A. El-Khouly

摘要

FeNb1-xHfxSb (x = 0.0, 0.10, 0.20) alloys were synthesized by successive induction melting and mechanical alloying (MA). Mass fluctuations followed by disorder scattering were present due to the difference in mass and size between Hf and Nb atoms. Disorder scattering largely affected the thermoelectric properties. Thermoelectric properties were investigated against temperatures from 300 to 800 K. The electrical conductivities of the parent FeNbSb alloy and the slightly doped FeNb0.9Hf0.1Sb samples exhibited semiconducting trends with smaller conductivity values over the entire temperature range. In contrast, the most doped FeNb0.8Hf0.2Sb sample showed a metal-like behavior. The metallic trend indicates that typical acoustic phonon scattering dominates the charge transfer. Seebeck coefficients increase remarkably with the temperature increasing due to Hf-doping at the studied doping range due to the remarkable effect of Hf-doping on the carrier concentration. The highest recorded power factor was obtained at 20 µWcm−1 K−2 for the highest Hf-doped FeNb0.8Ti0.2Sb alloy. The enhanced point-defect and electron–phonon scatterings remarkably contributed to a reduction in the lattice thermal conductivity and consequently improved thermoelectric figure of merit. The maximum figure of merit (zT) was observed for the same sample with a value of 0.17, recorded at 700 K.