bei Google ScholarTitelangaben
Exner, Jörg ; Albrecht, Gaby ; Schubert, Michael ; Stöcker, Thomas ; Hanft, Dominik ; Moos, Ralf:
NOx detection by pulsed polarization of YSZ films prepared by aerosol
deposition.
2016
Veranstaltung: 6th International Congress on Ceramics (ICC6)
, 21.-25.08.2016
, Dresden, Deutschland.
(Veranstaltungsbeitrag: Kongress/Konferenz/Symposium/Tagung
,
Poster
)
Abstract
The pulse-polarization measurement technique using YSZ electrolytes has already shown a great potential to detect low concentrations of NOx in exhaust gases. The pulse polarization method is based on the self-discharge of the electrodes measured after applying alternating voltage pulses. Until now, the electrolyte only exists in form of substrates. Our goal was to prepare a pulse polarization sensor using a planar setup to enable an easy integration within existing planar-type devices. In this study, highly dense YSZ films with thicknesses between 5 and 20 μm were prepared by aerosol deposition (AD) on alumina substrates. This technology bases upon a room temperature impact consolidation process (RTIC) to deposit dense solid films of ceramic materials on various substrates without using a high-temperature step during the coating process. Subsequently a platinum interdigital electrode structure was applied on top of the electrolyte by screen printing and sintering. This sensor setup was then tested in a quartz furnace at 420°C with varying NO and NO2 concentrations, ranging from 3 to 24 ppm in a base gas (10 % O2, 2 vol.-% H2O in N2). Our measurements indicate that all tested concentrations of NO as well as NO2 can be determined with sensitivities up to 190 mV per decade for NO2 and 90 mV per decade NO, therefore outperforming previous published data. Results also predict that even concentrations in the sub-ppm range could be measured. The sensor response was stable in case of NO2 for multiple cycles, while the sensitivity towards NO declined over time. This shows, that YSZ AD films generally show a high potential as sensor materials for nitrous gases.