Applications for Aerosol Deposition in the field of gas sensing

Titelangaben

Moos, Ralf:
Applications for Aerosol Deposition in the field of gas sensing.
2015
Veranstaltung: PACRIM 11, The 11th Pacific Rim Conference of Ceramic Societies , 30.08.-04.09.2015 , Jeju, Korea.
(Veranstaltungsbeitrag: Kongress/Konferenz/Symposium/Tagung , Vortrag )

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Abstract

Typically, gas sensors are ceramic devices. Since heater and electrical readout structures are made of noble metals, they are manufactured in ceramic technologies like tape technology (HTCC and LTCC) and classical thick-film techniques like screen-printing and firing. During firing, one has to deal with interdiffusion processes between substrate and gas sensitive film that may (partly) deteriorate the properties of the functional oxides. Some materials can even hardly be processed to sensor devices without decomposition.

Therefore, other techniques may be advantageous.

The Aerosol-Deposition-Method (ADM, also called Room Temperature Impact Consolidation, RTIC) allows producing dense ceramic films completely without any high-temperature process directly from an initial bulk powder on almost any substrate material. This contribution reviews applications for the ADM in the field of gas sensing.

Besides conventional conductometric gas sensors out of SnO2 and other metal oxides to detect environmentally harmful or dangerous substances, applications for temperature independent oxygen sensors are discussed, using SrTi1-xFexO3 or BaFe1-xTaxO3. Simultaneous co-deposition of inert and functional oxides to fine tune the sensing properties offers further promising prospects.

The Aerosol-Deposition-Method can also be applied for manufacturing solid state electrochemical gas sensors. An example for a nitrogen oxide sensor using the novel pulsed-polarization method, which attracted recently much attention with YSZ as solid electrolyte, is shown, however now operated at lower temperature due to the use of a Bismuth-based fast oxygen ion conductor.