Journal Article

PreJuSER-16640

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Properties of spark plasma sintered nanostructured Zn1 xSb

Birkel, C. S. ; Claudio, T.FZJ* ; Panthöfer, M. ; Birkel, A. ; Koll, D. ; Kieslich, G. ; Schmidt, J. ; Hermann, R.FZJ* ; Tremel, W.

2011
Wiley-VCH Weinheim

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Please use a persistent id in citations: doi:10.1002/pssa.201026665

Abstract: Engineering materials with specific physical properties has recently focused on the effect of nanoscopic inhomogeneities at the 10 nm scale. Such features are expected to scatter medium and long-wavelength phonons lowering thereby the thermal conductivity of the system without simultaneously decreasing the charge transport (phonon-glass electron-crystal concept). A new Zn1+xSb nanophase obtained by a wet chemical approach was densified by spark plasma sintering (SPS). Investigations on compounds subsumed as "Zn4Sb3" always suffer from its low thermal stability and the contamination of the nanoparticles with solvents and additives used in the synthesis. In order to gain insight into this compound's electronic properties we investigated a material free from remnants of the synthesis but contaminated with a small amount of well-characterized decomposition product, i.e., ZnSb. To investigate the influence of the sintering process on the densified samples, different SPS conditions were applied. Four different conditions were used with heating rates between 160 degrees and 230 degrees C/min, sintering temperatures between 130 and 190 degrees C and sintering times between 3 and 6 min. Powders from the surface of the pellets were subject to powder X-ray diffraction (XRD) yielding information about the surface composition. Small pieces of the pellets were also characterized using high-energy synchrotron radiation scattering in order to reveal the phase compositions inside the pellets. Small changes in the sintering conditions of the samples were found to have a large influence on the resulting sample compositions. In addition, the phase compositions on the surface differ significantly from the ones inside the pellets which show a much higher grade of decomposition. The density and morphology of the obtained pellets have been investigated by means of laser microscopy and scanning electron microscopy (SEM). The low density and porosity of the different pellets is a result of the graphite pressing tool which has to be used to ensure the temperature control during the SPS process. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Keyword(s): J ; intermetallics (auto) ; spark plasma sintering (auto) ; thermoelectrics (auto) ; zinc antimonide (auto)

Note: The Advanced Photon Source APS Argonne/Chicago is acknowledged for synchrotron radiation beam time. The DFG priority program SPP1386 "Nanostructured Thermoelectrics" is acknowledged for the support of this study. C.S.B. is a recipient of a fellowship from MATCOR, the Graduate School of Excellence of the State of Rhineland-Palatinate. R.H. acknowledges support from the Helmholtz-University Young Investigator Group "Lattices Dynamics in Emerging Functional Materials".

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Contributing Institute(s):

1. Streumethoden (PGI-4)
2. Jülich-Aachen Research Alliance - Fundamentals of Future Information Technology (JARA-FIT)
3. Streumethoden (JCNS-2)

Research Program(s):

1. Grundlagen für zukünftige Informationstechnologien (P42)
2. Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) (P55)

Appears in the scientific report 2011

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