Next Article in Journal
Strength and Character of R–X···π Interactions Involving Aromatic Amino Acid Sidechains in Protein-Ligand Complexes Derived from Crystal Structures in the Protein Data Bank
Next Article in Special Issue
Microstructure Evolution of Ag-Alloyed PbTe-Based Compounds and Implications for Thermoelectric Performance
Previous Article in Journal
CH3NH3Cl Assisted Solvent Engineering for Highly Crystallized and Large Grain Size Mixed-Composition (FAPbI3)0.85(MAPbBr3)0.15 Perovskites
Previous Article in Special Issue
Enhanced Thermoelectric Performance of Te-Doped Bi2Se3−xTex Bulks by Self-Propagating High-Temperature Synthesis
Article

Spark Plasma Sintering of Tungsten Oxides WOx (2.50 ≤ x ≤ 3): Phase Analysis and Thermoelectric Properties

1
Max-Planck-Institut für Chemische Physik fester Stoffe, 01187 Dresden, Germany
2
Fraunhofer Institut für Fertigungstechnik und Angewandte Materialforschung, 01277 Dresden, Germany
*
Authors to whom correspondence should be addressed.
Academic Editor: George S. Nolas
Crystals 2017, 7(9), 271; https://doi.org/10.3390/cryst7090271
Received: 26 July 2017 / Revised: 21 August 2017 / Accepted: 23 August 2017 / Published: 5 September 2017
(This article belongs to the Special Issue Materials Processing and Crystal Growth for Thermoelectrics)
The solid-state reaction of WO3 with W was studied in order to clarify the phase formation in the binary system W-O around the composition WOx (2.50 ≤ x ≤ 3) during spark plasma sintering (SPS). A new phase “WO2.82” is observed in the range 2.72 ≤ x ≤ 2.90 which might have the composition W12O34. The influence of the composition on the thermoelectric properties was investigated for 2.72 ≤ x ≤ 3. The Seebeck coefficient, electrical conductivity and electronic thermal conductivity are continuously tunable with the oxygen-to-tungsten ratio. The phase formation mainly affects the lattice thermal conductivity κlat which is significantly reduced until 700 K for the sample with the composition x = 2.84, which contains the phases W18O49 and “WO2.82”. In single-phase WO2.90 and multi-phase WOx materials (2.90 ≤ x ≤ 3), which contain crystallographic shear plane phases, a similar reduced κlat is observed only below 560 K and 550 K, respectively. Therefore, the composition range x < 2.90 in which the pentagonal column structural motif is formed might be more suitable for decreasing the lattice thermal conductivity at high temperatures. View Full-Text
Keywords: thermoelectric materials; spark plasma sintering; tungsten oxides; crystallographic shear plane phases thermoelectric materials; spark plasma sintering; tungsten oxides; crystallographic shear plane phases
Show Figures

Graphical abstract

MDPI and ACS Style

Kaiser, F.; Simon, P.; Burkhardt, U.; Kieback, B.; Grin, Y.; Veremchuk, I. Spark Plasma Sintering of Tungsten Oxides WOx (2.50 ≤ x ≤ 3): Phase Analysis and Thermoelectric Properties. Crystals 2017, 7, 271. https://doi.org/10.3390/cryst7090271

AMA Style

Kaiser F, Simon P, Burkhardt U, Kieback B, Grin Y, Veremchuk I. Spark Plasma Sintering of Tungsten Oxides WOx (2.50 ≤ x ≤ 3): Phase Analysis and Thermoelectric Properties. Crystals. 2017; 7(9):271. https://doi.org/10.3390/cryst7090271

Chicago/Turabian Style

Kaiser, Felix, Paul Simon, Ulrich Burkhardt, Bernd Kieback, Yuri Grin, and Igor Veremchuk. 2017. "Spark Plasma Sintering of Tungsten Oxides WOx (2.50 ≤ x ≤ 3): Phase Analysis and Thermoelectric Properties" Crystals 7, no. 9: 271. https://doi.org/10.3390/cryst7090271

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop