| 摘要 |
PURPOSE:To obtain a gas sensing element with no change with time, by adding a metallic oxide, such as Al, Cr or Y oxide, to SnZn2O4 and baking this mixture under a specific temperature condition. CONSTITUTION:SnO2 and ZnO are reacted with each other to prepare SnZn2O4, to which a substance represented by the formula M2O3 (wherein M represents Al, Cr or Y) is added by 0.01-5.0wt% in terms of the oxide. In the case where the amount of addition of the substance is less than 0.01wt%, the gas sensing element is not sufficiently improved in the change of electric resistance with time. On the other hand, an addition amount exceeding 5.0wt% lowers the sensitivity of the element to a combustible gas. The thus obtained powder is formed into a desired shape and is then baked at about 600-1,400 deg.C. The thus produced gas sensing element is stable in crystal and sintered body structure and has an extremely small change of electric resistance with time. |
