Toru Usami, Noboru Akao, Nobuyoshi Hara and Katsuhisa Sugimoto
Department of Metallurgy, Graduate School of Engineering, Tohoku University, Sendai 980-8579
An oxygen sensor with a Ag⋅YSZ (ZrO2-8 mol%Y2O3) composite thin film electrode deposited on a YSZ disk by ion-beam-sputtering (IBS) was developed. Compositions of the thin films tested were Ag-10 mol%YSZ and Ag-30 mol%YSZ. The performance of the oxygen sensors was examined at temperatures between 573 and 673 K. The mechanism of electrode reactions was inferred on the basis of the results obtained by an AC impedance method. The oxygen sensor with the Ag⋅YSZ composite thin film electrodes showed the Nernstian response in 1.0% oxygen at temperatures higher than 593 K. The lowest temperature for the Nernstian response was lower by 25 K than that reported for the sensor with a Ag thin film electrode. After a change in oxygen concentration, the response time of the sensor with the Ag-10 mol%YSZ electrode was shorter than that with the Ag-30 mol%YSZ electrode.
(Received July 10, 2001)
oyxgen sensor, yttria stabilized zirconia, Ag⋅YSZ composite thin film, ion-beam-sputter deposition, Nernstian response, response time
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