Reduced thermal conductivity by nanoscale intergrowths in perovskite like layered structure La2Ti2O

Journal article (2015)
Department
Aerospace Structures & Materials (Aerospace Engineering) (TU Delft)
Copyright: © 2015 American Institute of Physics
More Info
expand_more

Published Date

18-02-2015

Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Source:

Journal of Applied Physics, 117 (7), 2015

ISSN:

0021-8979

Faculty

Aerospace Engineering

Department

Aerospace Structures & Materials

Abstract

The effect of substitution and oxidation-reduction on the thermal conductivity of perovskite-like layered structure (PLS) ceramics was investigated in relation to mass contrast and non-stoichiometry. Sr (acceptor) was substituted on the A site, while Ta (donor) was substituted on the B site of La2Ti2O7. Substitution in PLS materials creates atomic scale disorders to accommodate the non-stoichiometry. High resolution transmission electron microscopy and X ray diffraction revealed that acceptor substitution in La2Ti2O7 produced nanoscale intergrowths of n?=?5 layered phase, while donor substitution produced nanoscale intergrowths of n?=?3 layered phase. As a result of these nanoscale intergrowths, the thermal conductivity value reduced by as much as ?20%. Pure La2Ti2O7 has a thermal conductivity value of ?1.3?W/m K which dropped to a value of ?1.12?W/m K for Sr doped La2Ti2O7 and ?0.93?W/m K for Ta doped La2Ti2O7 at 573?K.

Files

316956.pdf
(pdf | 1.32 Mb)