Thermoelectric properties of novel skutterudites with didymium: DDy(Fe1−xCox)4Sb12 and DDy(Fe1−xNix)4Sb12

Abstract In order to improve the thermoelectric properties via efficient phonon scattering Didymium (DD), a mixture of Pr and Nd, was used as a new filler in ternary skutterudites (Fe 1− x Co x ) 4 Sb 12 and (Fe 1− x Ni x ) 4 Sb 12 . DD-filling levels have been determined from combined data of X-ray powder diffraction and electron microprobe analyses (EMPA). Thermoelectric properties have been characterized by measurements of electrical resistivity, thermopower and thermal conductivity in the temperature range from 4.3 to 800 K. The effect of nanostructuring in DD 0.4 Fe 2 Co 2 Sb 12 was elucidated from a comparison of both micro-powder (ground in a WC-mortar, ∼10 μm) and nano-powder (ball-milled, ∼150 nm), both hot pressed under identical conditions. The figure of merit ZT depends on the Fe/Co and Ni/Co-contents, respectively, reaching ZT > 1. At low temperatures the nanostructured material exhibits a higher thermoelectric figure of merit. The Vickers hardness was measured for all samples being higher for the nanostructured material.

[1]  Ctirad Uher,et al.  Skutterudite-Based Thermoelectrics , 2005 .

[2]  H. Takizawa,et al.  Atom insertion into the CoSb3 skutterudite host lattice under high pressure , 1999 .

[3]  C. Uher,et al.  Effect of Ni on the transport and magnetic properties of (formula presented) , 2002 .

[4]  P. Fischer,et al.  Magnetic behaviour of PrFe4Sb12 and NdFe4Sb12 skutterudites , 2002 .

[5]  C. Uher,et al.  Low thermal conductivity and high thermoelectric figure of merit in n-type BaxYbyCo4Sb12 double-filled skutterudites , 2008 .

[6]  Berger,et al.  Crystal field effects and thermoelectric properties of PrFe 4 Sb 12 skutterudite , 2002 .

[7]  T. Roisnel,et al.  WinPLOTR: A Windows Tool for Powder Diffraction Pattern Analysis , 2001 .

[8]  Han Li,et al.  High performance InxCeyCo4Sb12 thermoelectric materials with in situ forming nanostructured InSb phase , 2009 .

[9]  T. Ebel,et al.  Rare earth and uranium transition metal pnictides with LaFe4P12 structure , 1995 .

[10]  E. Bauer,et al.  Magnetic and thermoelectric features of PryFe4−x(Ni,Co)xSb12 , 2004 .

[11]  A. Bjørseth,et al.  Compounds with the Skutterudite Type Crystal Structure. III. Structural Data for Arsenides and Antimonides. , 1974 .

[12]  M. Rotter,et al.  Lattice dynamics of skutterudites: Inelastic x-ray scattering on CoSb 3 , 2008 .

[13]  Jihui Yang,et al.  Dual-frequency resonant phonon scattering in BaxRyCo4Sb12 （R=La, Ce and Sr） , 2007 .

[14]  C. Godart,et al.  A novel skutterudite phase in the Ni–Sb–Sn system: phase equilibria and physical properties , 2002 .

[15]  Yu Zhang,et al.  Nanostructured Co1-xNixSb3 skutterudites : Synthesis, thermoelectric properties, and theoretical modeling , 2003 .