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| Abstract No.: |
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Scheduled at:
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Friday, June 09, 2017, Hall 14 11:20 AM
Electronics & Sensoric
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| Title: |
Correlation of the process-structure-thermoelectric relationship of thermal spray synthesized sub-stoichiometry TiO2-x
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| Authors: |
Hwasoo Lee* / Stony Brook University, USA
Sanjay Sampath / Center for Thermal Spray Research / Stony Brook University, USA
Ramachandran Chidambaram-Seshadri/ Center for Thermal Spray Research / Stony Brook University, USA
Su Jung Han/ Center for Thermal Spray Research / Stony Brook University, USA
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| Abstract: |
The thermoelectric properties of sub-stoichiometric TiO2-x deposits prepared by thermal spray deposition process (APS, HVOF) are investigated from room temperature to 750 K. 18 different variants of TiO2-x deposit conditions were characterized for phase, microstructure and electrical transport. Started with two types of feedstock variants, TiO1.9 and TiO1.7, both of these materials were subject to two types of plasma torches with systematic changes in H2 in the plume for each torch to control the temperature and decomposition. For reference, a high velocity oxy fuel spray torch was used. Two samples show promising ZT values of > 0.1 and the best was achieved with the cascade 0 H2 where Seebeck coefficients of -230 ¼V K-1 and electrical conductivity of 5.4 8× 103 S m-1 are obtained resulting in a power factor of 2.9 ¼W cm-1 K-2 at temperatures of 750 K. The lamellar deposits resultant provides thermal conductivity of 1.65 W m-1 K-1 at 750 K and associated ZT value of 0.132. Detailed XRD results show a pattern indicating that higher H2 in the torch leads to greater decomposition and formation of the Ti4O7 phase which is known to have higher electrical conductivity but comes with a concomitant loss in Seebeck coefficient. The peculiar results of ZT 0.132 was revisited through repeated trials and found the results to be highly reproducible through at least 6 iterations with values ranging from 0.125 to 0.135. Further process was made in this effort by building multilayer power harvesting devices through layered manufacturing and patterning which will be shared in Young Professionals.
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