Liang, XinClarke, David2014-03-072013Liang, Xin, and David R. Clarke. 2014. Relation between thermolectric properties and phase equilibria in the \(ZnO–In_2O_3\) binary system. Acta Materialia 63: 191-201.1359-6454http://nrs.harvard.edu/urn-3:HUL.InstRepos:11870371The electrical conductivities, Seebeck coefficients and thermal conductivities across the ZnO–In\(_2\)O\(_3\) binary system are reported and related to the phase compositions and microstructures present at 1150 and 1250 °C. The ZnO–In\(_2\)O\(_3\) binary system is of particular interest as it contains a variety of different types of phases, superlattice (modular) phases, solid solutions, two-phase regions and crystallographic features. Throughout much of the phase diagram, the thermal conductivities are less than 2 W m\(^{−1}\) K\(^{−1}\), being limited by both solid solution disorder and thermal resistance due to the presence of InO/ZnO interfaces. Across the phase diagram, irrespective of the actual phases, the materials behave at high temperatures (800 °C) as free-electron conductors with the Seebeck coefficient and electron conductivity satisfying the Jonker’s relationship. In the two-phase regions of the phase diagram, the values of the power factor and figure of merit (ZT) are consistent with a simple law of mixtures, weighted according to the volume fractions of the two phases. Although the largest values of electrical conductivity and Seebeck coefficient occur over a range of composition centered at 40 m/o InO\(_{1.5}\), the maximum ZT and power factors are observed at k = 4 (33 m/o InO\(_{1.5}\)). In contrast to the other modular phases at 1250 °C and below, this phase is hexagonal rather than rhombohedral.en-USThermoelectricsOxideMicrostructureSuperlatticeTwo-phase materialsJournal Article2013-10-15Xin Liang and David R. Clarke2014-03-0710.1016/j.actamat.2013.10.027