Enhancement of thermoelectric figure-of-merit at low temperatures by titanium substitution for hafnium in n-type half-Heuslers Hf0.75−xTixZr0.25NiSn0.99Sb0.01

Abstract The effect of titanium (Ti) substitution for hafnium (Hf) on thermoelectric properties of (Hf, Zr)-based n-type half-Heuslers: Hf0.75−xTixZr0.25NiSn0.99Sb0.01, has been studied. The samples are made by arc melting followed by ball milling and hot pressing via the nanostructuring approach. A peak thermoelectric figure-of-merit (ZT) of ∼1.0 is achieved at 500 °C in samples with a composition of Hf0.5Zr0.25Ti0.25NiSn0.99Sb0.01 due to a slight increase in carrier concentration and also a lower thermal conductivity caused by Ti. The ZT values below 500 °C of hot pressed Hf0.5Zr0.25Ti0.25NiSn0.99Sb0.01 samples are significantly higher than those of the same way prepared Hf0.75Zr0.25NiSn0.99Sb0.01 samples at each temperature, which are very much desired for mid-range temperature applications such as waste heat recovery in automobiles.

[1]  Hohyun Lee,et al.  Enhanced thermoelectric figure-of-merit in nanostructured p-type silicon germanium bulk alloys. , 2008, Nano letters.

[2]  Hui Wang,et al.  Stronger phonon scattering by larger differences in atomic mass and size in p-type half-Heuslers Hf1−xTixCoSb0.8Sn0.2 , 2012 .

[3]  Band gap and stability in the ternary intermetallic compounds NiSnM (M=Ti,Zr,Hf): A first-principles study. , 1994, Physical review. B, Condensed matter.

[4]  G. Meisner,et al.  Strain field fluctuation effects on lattice thermal conductivity of ZrNiSn-based thermoelectric compounds , 2004 .

[5]  J. Fleurial,et al.  Skutterudites: A new class of promising thermoelectric materials , 1994 .

[6]  M. Kanatzidis,et al.  Structural stability of Ni-containing half-Heusler compounds , 2000 .

[7]  Terry M. Tritt,et al.  Effect of substitutions on the thermoelectric figure of merit of half-Heusler phases at 800 °C , 2006 .

[8]  Xiangyang Huang,et al.  The high temperature thermoelectric performances of Zr0.5Hf0.5Ni0.8Pd0.2Sn0.99Sb0.01 alloy with nanophase inclusions , 2006 .

[9]  R. K. Williams,et al.  Filled Skutterudite Antimonides: A New Class of Thermoelectric Materials , 1996, Science.

[10]  Di Wu,et al.  Half-Heusler phases and nanocomposites as emerging high-ZT thermoelectric materials , 2011 .

[11]  Gang Chen,et al.  Enhancement in Thermoelectric Figure‐Of‐Merit of an N‐Type Half‐Heusler Compound by the Nanocomposite Approach , 2011 .

[12]  Gang Chen,et al.  Enhanced thermoelectric figure of merit of p-type half-Heuslers. , 2011, Nano letters.

[13]  M. A. Kouacou,et al.  Crossover from semiconductor to magnetic metal in semi-Heusler phases as a function of valence electron concentration , 1998 .

[14]  G. Poon.  Chapter 2 Electronic and thermoelectric properties of Half-Heusler alloys , 2001 .

[15]  Andrew G. Glen,et al.  APPL , 2001 .

[16]  M. Dresselhaus,et al.  High-Thermoelectric Performance of Nanostructured Bismuth Antimony Telluride Bulk Alloys , 2008, Science.

[17]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[18]  Joseph Callaway,et al.  Effect of Point Imperfections on Lattice Thermal Conductivity , 1960 .

[19]  Qiang Shen,et al.  Effects of partial substitution of Ni by Pd on the thermoelectric properties of ZrNiSn-based half-Heusler compounds , 2001 .

[20]  I. Dasgupta,et al.  Electronic structure and magnetism in half-Heusler compounds , 2003 .

[21]  Lidong Chen,et al.  Thermoelectric properties of p-type Fe-doped TiCoSb half-Heusler compounds , 2007 .

[22]  Jihui Yang,et al.  Evaluation of Half‐Heusler Compounds as Thermoelectric Materials Based on the Calculated Electrical Transport Properties , 2008 .

[23]  J. Toboła,et al.  Electronic phase diagram of the XTZ (X=Fe, Co, Ni; T=Ti, V, Zr, Nb, Mn; Z=Sn, Sb) semi-Heusler compounds , 2000 .

[24]  D. Rowe.  CRC Handbook of Thermoelectrics , 1995 .

[25]  Terry M. Tritt,et al.  Recent trends in thermoelectric materials research , 2001 .

[26]  Remo Guidieri.  Res , 1995, RES: Anthropology and Aesthetics.

[27]  S. Poon,et al.  (Zr,Hf)Co(Sb,Sn) half-Heusler phases as high-temperature (>700°C) p-type thermoelectric materials , 2008 .

[28]  S. Poon,et al.  Thermoelectric properties of semimetallic (Zr, Hf)CoSb half-Heusler phases , 2000 .