Structure design and process improvement of planar oxygen sensor

A planar oxygen sensor with yttria stabilized zirconia (YSZ) based on high-temperature co-fired ceramic (HTCC) technology is presented in this paper. To protect the electrode from the exhaust gas, a porous layer is printed on the surface of the outer electrode. Also, an inner electrode is in contact with air reference atmosphere. Moreover, a heating element with a dissipative resistance is embedded into sensor structure to achieve stable and sufficient high temperatures for fast light-off time and air/fuel ratio (A/F) detection. The sintering behaviors of alumina/platinum/zirconia are studied and the co-fired mismatch caused by the different shrinkage rates and multilayer configurations in multi-layer different material structure are investigated. Furthermore, the thermal stress in this planar oxygen sensor from the cold start process is simulated and discussed.