Patent attributes
A technology which makes it possible to prolong the service life of a porous electrode constituted by a sintered body of an electrode metal material and a ceramic material, and the service life of an NOx sensor element having the porous electrode. The porous electrode is produced so as to have a total pore volute of at least 0.013 ml/g and a peak pore diameter of at least 0.31 μm as measured by mercury penetration method, by a process wherein a composition which includes the electrode material and the ceramic material and to which a vanishable solid material that vanishes by firing is formed into a thin film, which is then fired to form the sintered body which consists of the electrode material and the ceramic material and which has a multiplicity of pores formed as a result of vanishing of the vanishable solid material.