Tuning of the electronic and phononic properties of NbFeSb half-Heusler compound by Sn/Hf co-doping. (1st September 2020)

• Record Type: Journal Article
• Authors: Mohamed, M.A.A.; Ibrahim, E.M.M.; Rodriguez, N.P.; Hampel, S.; Büchner, B.; Schierning, G.; Nielsch, K.; He, R.
• Is Part Of: Acta materialia. Volume 196(2020)
• Page Start: 669
• Page End: 676
• Publication Date: 2020-09-01
• Subjects: NbFeSb -- Sn/Hf co-doping -- Phononic -- Thermoelectric; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2020.07.028
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: Pure phase NbFeSb1-x Snx (where x = 0, 0.04, 0.08, 0.12, 0.16) half-Heusler samples were prepared by direct mechanical alloying followed by spark plasma sintering. The results showed that the substitution of Sb by Sn can effectively enhance the peak figure of merit ( ZT ) to 0.55 at 923 K in NbFeSb0.88 Sn0.12 through optimized carrier concentration. To further reduce the lattice thermal conductivity ( κL ), we substituted Nb by Hf to enhance the point defect scattering of phonon transport. A maximum reduction of ~80% in κL was observed in Nb0.8 Hf0.2 FeSb0.88 Sn0.12 when compared to undoped NbFeSb at 573 K. We realized a minimum κL of ~2.96 W m −1 K −1 at 673 K and a peak ZT of ~0.82 at 973 K for Nb0.88 Hf0.12 FeSb0.88 Sn0.12 . Graphical abstract: Image, graphical abstract