A current challenge in the thermoelectric field is the discovery of new materials which are inexpensive, easy to synthesize, and comprised of earth-abundant elements. Recently natural mineral tetrahedrites received great interest from thermoelectric community because of their non-toxicity, environmental friendliness and relatively high abundance. Natural "tetrahedrite" exists as a solid solution of tetrahedrite (Cu12Sb4S13) and tennantite (Cu12As4S13), where the Cu atoms are partially replaced by transition metal elements such as Zn, Fe, Mn, Hg or Ni [1-3]. The tetrahedrite/tennantite mineral family is the most widespread sulfosalt on Earth. The ZT values obtained for pure synthetic tetrahedrite Cu12Sb4S13 is 0.56 at 673 K [4]. Synthetic tetrahedrites were variously doped, with interesting results for Ni doped samples with a maximum ZT of 0.7 at 665 K for Cu10.5Ni1.5Sb4S13 [5]. All the synthesis reported in thermoelectric literature are based on a direct melting method starting from pure constituent elements and are characterized by high pressures, high temperatures and long time (up to 2-3 week) [4-6]. In this work, we developed a new fast synthesis and sintering method to obtain Ni-Zn substituted tetrahedrite pellets by means of the combination of ball milling and open die pressing sintering (ODP) methods [7]. X-Ray diffraction (with a profile Rietveld refinements) and Scanning Electron Microscope (equipped with energy dispersive X-Ray spectroscopy) were employed for a structural, morphological and compositional characterization of the obtained samples. Furthermore, the samples were thermoelectric characterized by electrical conductivity and Seebeck coefficient measurements, and Laser Flash Analysis for the thermal conductivity
Fast synthesis and sintering of Zn and Ni substituted tetrahedrite for thermoelectric applications
S Fiameni;S Battiston;S Fasolin;C Fanciulli;A Famengo;S Boldrini;M Fabrizio
2015
Abstract
A current challenge in the thermoelectric field is the discovery of new materials which are inexpensive, easy to synthesize, and comprised of earth-abundant elements. Recently natural mineral tetrahedrites received great interest from thermoelectric community because of their non-toxicity, environmental friendliness and relatively high abundance. Natural "tetrahedrite" exists as a solid solution of tetrahedrite (Cu12Sb4S13) and tennantite (Cu12As4S13), where the Cu atoms are partially replaced by transition metal elements such as Zn, Fe, Mn, Hg or Ni [1-3]. The tetrahedrite/tennantite mineral family is the most widespread sulfosalt on Earth. The ZT values obtained for pure synthetic tetrahedrite Cu12Sb4S13 is 0.56 at 673 K [4]. Synthetic tetrahedrites were variously doped, with interesting results for Ni doped samples with a maximum ZT of 0.7 at 665 K for Cu10.5Ni1.5Sb4S13 [5]. All the synthesis reported in thermoelectric literature are based on a direct melting method starting from pure constituent elements and are characterized by high pressures, high temperatures and long time (up to 2-3 week) [4-6]. In this work, we developed a new fast synthesis and sintering method to obtain Ni-Zn substituted tetrahedrite pellets by means of the combination of ball milling and open die pressing sintering (ODP) methods [7]. X-Ray diffraction (with a profile Rietveld refinements) and Scanning Electron Microscope (equipped with energy dispersive X-Ray spectroscopy) were employed for a structural, morphological and compositional characterization of the obtained samples. Furthermore, the samples were thermoelectric characterized by electrical conductivity and Seebeck coefficient measurements, and Laser Flash Analysis for the thermal conductivityI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
