PURPOSE: To enhance mechanical strength, electrode close adhesiveness and oxygen ionizing capacity, by roughening the surface of the solid electrolyte for an oxygen sensor so that the holdability of strength, the close adhesiveness with an electrode, the holdability of oxygen ion conductivity are well-balanced with each other.
CONSTITUTION: When the surface roughness of a solid electrolyte is made large, mechanical strength becomes low and electrode close adhesiveness and the holdability of oxygen ion conductivity are enhanced. Then, when due regard to strength holding max. surface roughness Rs(max), electrode close adhesiveness strength min. surface roughness Ra(min) and oxygen ion conductivity holding min. roughness Rc(min), surface roughness is determined. For example, when mechanical strength is mainly considered, surface roughness is set to Rc (min)≤R≤Rs(max). When the solid electrolyte is 8mol yttria stabilized zirconia, surface roughness is set to 0.8s≤R≤1.2s because of Rs(max)=1.2s, Rc(min)=0.8s and Pa(min)=0.7s. Herein, (s) is surface roughness and equal to μm. Therefore, mechanical strength can be increased without lowering the function of an oxygen sensor.
NAKAZAWA MITSUHIRO
ASADA AKIYOSHI
OSANAI YUTAKA
