Title

Thin film nanocomposites for thermoelectric applications

Document Type

Conference Proceeding

Date of Original Version

11-15-2010

Abstract

Thin film nanocomposites comprised of refractory metals and alumina were initially considered for thermal barrier coatings, since the large number of interfaces between the ceramic and metallic phases lead to considerable phonon scattering and ultra low thermal conductivity. When nanocomposites based on NiCoCrAlY and alumina were optimized for electrical and thermal conductivity, they showed considerable promise as thermoelectrics. Therefore, by replacing the alumina phase in these nanpocomposites with wide bandgap oxide semiconductors such as indium tin oxide (ITO) and zinc oxide (AZO), nanocomposites with extremely large and repeatable Seebeck coefficients were realized. Sputtering was selected as the deposition method of choice to prepare the nanocomposites, since it is a non-equilibrium, low deposition temperature process and thus, greatly reduces the tendency for particle agglomeration during deposition. Composite sputtering targets were prepared by plasma spraying optimized mixtures of NiCoCrAlY and ITO onto a stainless steel backing plates. The resulting NiCoCrAlY:ITO nanocomposite films exhibited thermoelectric powers on the order of 8000μV/°C at 1125°C, making them suitable for high temperature energy harvesting devices.

Publication Title

Ceramic Transactions

Volume

223

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