| 摘要 |
PURPOSE:To sufficiently protect a Pt electrode against gaseous sulfurous acid by forming porous layers consisting of a mixture composed of Al2O3 and Au on the Pt electrode. CONSTITUTION:The porous plates 2 consisting of Pt are formed on both surfaces of a solid electrolyte plate 1 having ionic conductivity of a prescribed gas, for example, a stabilized zirconia plate having the ionic conductivity of gaseous O2. Further, the porous protective layers 7 consisting of the mixture composed of the Al2O3 and Au are formed on both the surface of the electrodes 2. The layers 7 receive the influence of heating to about 1,000 deg.C in, for example, a sate of sealing a cap to the electrolyte plate, but the Au is hardly mixed with the Pt of the electrode 2 and, therefore, electrode 2 is eventually coated with the layers consisting of the mixture composed of the Al2O3 and Au. The electrode efficiency is, therefore, not degraded and in addition, the Pt electrode is sufficiently protected against the gaseous sulfurous acid. The sensor is thus kept free from the adverse influence on its life. |
