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Electro-migration of Zinc during current-assisted pressure sintering of β-Zn4Sb3 – effect of process parameters and its influence on the thermoelectric properties

Published online by Cambridge University Press:  25 July 2011

T. Dasgupta
Affiliation:
German Aerospace Center (DLR), Institute of Materials Research, D-51170, Cologne, Germany,
C. Stiewe
Affiliation:
German Aerospace Center (DLR), Institute of Materials Research, D-51170, Cologne, Germany,
L. Boettcher
Affiliation:
German Aerospace Center (DLR), Institute of Materials Research, D-51170, Cologne, Germany,
H. Yin
Affiliation:
University of Aarhus, Department of Chemistry and iNANO, Langelandsgade 140, DK-8000, Aarhus, Denmark
B.B. Iversen
Affiliation:
University of Aarhus, Department of Chemistry and iNANO, Langelandsgade 140, DK-8000, Aarhus, Denmark
E. Mueller
Affiliation:
German Aerospace Center (DLR), Institute of Materials Research, D-51170, Cologne, Germany,
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Abstract

Compaction of β-Zn4Sb3 was carried out by current-assisted short term sintering under pressure (STS) using different material and process parameters. Surface Seebeck mapping (PSM) of the compacted specimens (along the uniaxial pressing direction) shows a wide gradation ranging from ∼40–180 μV/K due to electro-migration of Zinc along the current direction. The wide distribution of S corresponds to a mixture of Zn-Sb phases [1] which arise depending on the extent of Zinc migration during the STS process. Variation in the material and process parameters (average particle size, heating rate, compaction time/temperature) results in different spatial distribution of S. Measurements of electrical (σ), thermal (κ) conductivities and Seebeck (S) coefficients between room temperature and 523 K were carried out on two specimens having different average S values and distributions as observed by the PSM. The results indicate an increase in the lattice thermal conductivity (κL) and subsequent lower ZT in the specimens compared to the reported values for β-Zn4Sb3.

Type
Research Article
Copyright
Copyright © Materials Research Society 2011

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References

REFERENCES

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