抄録
Gas detection characteristics of p-type semiconducting MgCr2O4-TiO2 ceramics are discussed for diluted H2, NH3, C2H4, and CO gases in air. These ceramics were produced by sintering mixed oxide powders with 1.0 wt% doping of CaO, SnO2, Nb2O5, ZnO, or ZrO2. Adsorption and desorption of these gases were detected by the change of electrical resistance. It was found that the resistance change followed first-order reversible reaction as induced by the change of the potential barrier height at the grain boundaries of the ceramics. The dissociation constants of the first-order reaction agreed well with those derived from the fitting to the Langmuir isotherm equation. Dopant dependent characteristics are also discussed for respective gases.
