Development of resistive oxygen sensors based on cerium oxide thick film

It is important to shorten the response time of resistive oxygen sensor in order to reduce harmful emission of automobiles. The diffusion and surface reaction theory tells us that reducing particle size leads to shortening the response time. The fine ceria powder was prepared a by new precipitation method and the oxygen sensors having ceria thick film with the particle size of 120 nm were fabricated using fine ceria (cerium oxide) powder. The thick film exhibited good adhesion to alumina substrate. The value of n in R proportional to P(O-2)(1/n) at 1073 and 1173 K were 6.2 and 6.4 in the oxygen partial pressures range from 10(-13) to 10(5) Pa, respectively. The response time for the sensor was 22 and 12 ms at 1073 and 1173 K, respectively. The sensor fabricated in this study showed fast response.