Conductometric temperature independent oxygen and NO sensors of BaFe0.7Ta0.3O3-δ produced by aerosol deposition method (ADM)

Titelangaben

Bektas, Murat ; Hanft, Dominik ; Schönauer-Kamin, Daniela ; Stöcker, Thomas ; Hagen, Gunter ; Moos, Ralf:
Conductometric temperature independent oxygen and NO sensors of BaFe0.7Ta0.3O3-δ produced by aerosol deposition method (ADM).
2015
Veranstaltung: 90. DKG Jahrestagung / Symposium Hochleistungskeramik 2015 , 15.-19.03.2015 , Bayreuth, Deutschland.
(Veranstaltungsbeitrag: Kongress/Konferenz/Symposium/Tagung , Poster )

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Abstract

The sensing properties of the conductometric gas sensor material BaFe1-xTaxO3-δ (BFT) were studied between x = 0.1 and 0.5. BFT fine powders were prepared by the mixed-oxide technique. Perovskite structure could be clarified by XRD for powders calcined at 1350 °C. BFT thick films of around 5μm thickness were successfully deposited by the novel aerosol deposition method (ADM) on alumina substrates with Pt electrodes in four-wire configuration. With ADM, thick and dense ceramic films can be deposited at room temperature with a carrier gas under rough vacuum.

The electrical response of the films was investigated first under various oxygen concentrations and in a temperature range between 350 and 900 °C. Between 700 and 900 °C, the sample conductance of BaFe0.7Ta0.3O3-δ (BFT30) is highly oxygen dependent but almost not temperature dependent. BFT30 responds fast and reproducibly to changing oxygen partial pressures even at 350 °C. The cross sensitivity of coated samples was investigated in environments with various gases (C3H8, NO, NO2, CO, CO2, and H2O) at a constant oxygen partial pressure between 350 and 800 °C. BFT30 exhibits excellent sensing properties to NO between 300 and 450 °C in the range from 2.5 to 1000 ppm NO with a high selectivity towards all other examined gas species. This semiconductor ceramic material is a good candidate for a temperature independent oxygen sensor at high temperatures and as a NO sensor in ambient air at low temperatures.