Spinel-based NiMn2O4 negative temperature coefficient (NTC) thermistor thick films produced by the Aerosol Deposition Method (ADM)

Titelangaben

Bruckner, Michaela ; Münch, Christian ; Schuurman, Sophie ; Poulain, Veronique ; Kita, Jaroslaw ; Moos, Ralf:
Spinel-based NiMn2O4 negative temperature coefficient (NTC) thermistor thick films produced by the Aerosol Deposition Method (ADM).
2017
Veranstaltung: 92. DKG Jahrestagung & Symposium Hochleistungskeramik 2017 / 92st DKG Annual Conference & Symposium on High-Performance Ceramics 2017 , 19.03.2017 – 22.03.2017 , Berlin, Germany.
(Veranstaltungsbeitrag: Kongress/Konferenz/Symposium/Tagung , Vortrag )

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Abstract

Nickel manganese oxides are well-known semiconducting ceramics whose electrical resistance decreases exponentially with increasing temperature. Due to their high (negative) temperature coefficient (NTCR), they are well suited and widely used for temperature sensor applications. Conventional NTC thermistors are produced by sinteringbased methods such as pressing, extrusion or film casting. These methods are very time-consuming and energy-intensive. In this work, we present a novel spray coating process called aerosol deposition method (ADM) to produce dense ceramic NTCR films at room temperature directly from the initial ceramic powder. Using this method, nanocrystalline single-phase spinel NiMn2O4 thick films were successfully deposited on stiff substrates such as alumina, steel, silicon as well as on flexible substrates such as polyimide films. The electrical characterisation was conducted on films deposited on alumina substrates with screen-printed electrode structures. The electrical NTCR properties of the deposited, annealed and aged thick films were characterized in a silicone oil thermostatic bath between 25 °C and 85 °C. On the basis of these results, the reproducibility and the drift stability of the electric resistance R and the B constant were determined. Additionally, the structure and morphology of the deposited and annealed NiMn2O4 films were characterized with SEM and XRD.