Effect of nanostructure on the thermal conductivity of La-doped SrTiO3 ceramics

A series of La-doped (10 at%) SrTiO3 ceramics, with grain sizes ranging from 6 micron to 24 nm, were prepared from nanocrystalline powders using high-pressure field assisted sintering (HP-FAST). A progressive reduction of thermal conductivity, kappa, with decreasing grain size was observed. At room...

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Bibliographic Details
Published in:Journal of the European Ceramic Society 2014-02, Vol.34 (2), p.307-316
Main Authors: Buscaglia, M T, Maglia, F, Anselmi-Tamburini, U, Marre, D, Pallecchi, I, Ianculescu, A, Canu, G, Viviani, M, Fabrizio, M, Buscaglia, V
Format: Article
Language:English
Subjects:
Ceramics
Grain size
Nanocomposites
Nanomaterials
Nanostructure
Reduction
Strontium titanates
Thermal conductivity
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Summary:A series of La-doped (10 at%) SrTiO3 ceramics, with grain sizes ranging from 6 micron to 24 nm, were prepared from nanocrystalline powders using high-pressure field assisted sintering (HP-FAST). A progressive reduction of thermal conductivity, kappa, with decreasing grain size was observed. At room temperature, kappa of the ceramic with a grain size of 24 nm (1.2 W/ mK) was one order of magnitude lower than that of undoped single crystals. The strong suppression of kappa was ascribed to the high concentration of lattice defects, the increased contribution of grain boundaries to phonon scattering when the grain size was reduced to the nanoscale and a moderate amount (10-15 vol%) of nanopores. The results showed that nanostructure formation can be a successful strategy to attain a considerable reduction of kappa in heavily doped bulk oxide ceramics. The low electrical conductivity of the La-doped SrTiO3 nanoceramics represents a major obstacle for thermoelectric applications.
ISSN:0955-2219
DOI:10.1016/j.jeurceramsoc.2013.08.009