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Title: A new n-type half-Heusler thermoelectric material NbCoSb

Highlights: • Half-Heusler alloy NbCoSb with 19 valence electron count was studied as TE material. • It is surprising that NbCoSb is n-type. • A maximum ZT of ∼0.4 is achieved at 700 °C without optimization. • It opens up a new route to develop new half-Heusler thermoelectric materials. • It is very interesting that a traditionally thought of VEC of 18 is not required. - Abstract: We surprisingly made a new n-type thermoelectric compound NbCoSb with half-Heusler (HH) structure having valence electron count of 19, different from the traditional 18, which opens up a new route to develop new half-Heusler thermoelectric materials not following the traditional valence electron count of 18. The samples are made by arc melting followed by ball milling and hot pressing. The effect of hot pressing temperature on the thermoelectric properties of NbCoSb samples has been studied. A maximum thermoelectric figure-of-merit (ZT) of ∼0.4 is achieved at 700 °C in NbCoSb sample that is hot pressed at 1000 °C. This work add a new member to HH compounds for thermoelectric applications, although the peak ZT of ∼0.4 is still lower than that of the traditional HHs. Moreover, it is very interesting to see that amore » traditionally thought of valence electron counts of 18 is not required.« less
Authors:
 [1] ;  [2] ; ; ; ; ; ;  [3] ;  [1] ;  [3]
  1. Center for Advanced Materials and Energy, Xihua University, Chengdu, Sichuan 610039 (China)
  2. (United States)
  3. Department of Physics and TcSUH, University of Houston, Houston, TX 77204 (United States)
Publication Date:
OSTI Identifier:
22475962
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 70; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANTIMONY COMPOUNDS; COBALT COMPOUNDS; HEUSLER ALLOYS; HOT PRESSING; MELTING; NIOBIUM COMPOUNDS; N-TYPE CONDUCTORS; SEMICONDUCTOR MATERIALS; THERMAL CONDUCTIVITY; THERMOELECTRIC MATERIALS; THERMOELECTRIC PROPERTIES; X-RAY DIFFRACTION