| 摘要 |
PURPOSE:To obtain a detecting element having excellent gas selectivity by a method wherein a pair of electrodes each provided with a coating having a specific gas-sensing material as a main component are arranged on a gas-sensing base body formed of a valence control type semiconductor material, and one electrode, made to contain Cr ions, is made to serve as a heating electrode. CONSTITUTION:Concave grooves are provided at a distance t between the respective edge lines on the opposite surfaces of a base body 11 prepared by molding under pressure a gas-sensing material of a valence control type semiconductor having SnO2, ZnO, etc. as main components, and by baking the same thereafter. An oxidation-resisting metal wire made of Pt or the like, which is coated with a gas-sensing material 15 having the valence control type semiconductor material as a main component and containing Cr ions, is bonded as a heating electrode 12' to one groove. To the other groove, a metal wire made of Pt or the like, which is coated with a material 14 having a higher electric resistance than that of the material 15, is bonded as an electrode 12. CO of a mixed gas of CO and C2H5OH, for instance, is measured with high sensitivity from a change in the electric resistance either between the terminal 131 of the electrode 12 and the terminal 134 of the electrode 12' or between the terminals 132 and 133. |
