Studies on Conductance and Gas-sensing Properties of Y_1-x Mg_x FeO₃

The paper reports the preparation and the gas-sensing properties of Y_1-x Mg_x FeO₃ prepared by chemical co-precipitation method. Y₂O₃, Fe（NO₃）₃·H₂ O, Mg（NO₃）₂ and HNO₃ were used as starting materials. Y₂O₃ was dissolved in HNO₃ and mixed with Fe（NO₃）₃ and Mg（NO₃）₂, solution according to intended ratio, the （NH₄）₂CO₃ solution was dropped into the mixed solution to make Fe³⁺ Mg²⁺ and Y³⁺ coprecipitate. The coprecipitate were washed bydistilled Water, filtered, dried at 100℃, milled and calcined at 900℃ for 4h Mg²⁺ doping decreases the lattice constants and size of the material- When x≤0.8, the curie temperature of Y_1-x Mg_x FeO₃ is 100℃ than that of YFeO₃ and the conductivity of the sensor based on Y_1-xMg_x FeO₃ is higher than that of the sensor based on YFeO₃ . The reason forit is that Mg²⁺ doping forms Many holes Which can be indicated by the equation Mg_Y^x →Mg_Y' +h.The sensitivity to C₂ H₅ OH of the sensor based on Y_1-xMg_x FeO₃, is higher than that of sensorbased on YFeO₃ , but the sensitivity to othe gases of the sensor based on Y_1-xMgFeO₃ , is almost equal to that of sensor based on YFeO₃ which may be bouse Mg²⁺ play a cataytic rolein the reaction of C₂ H₅ OH oxidation. The sensor besed on Y_0.94 Mg_0.06 FeO₃ exhibits highestsensitivity to C₂ H₅ OH at 257℃, and S_{4.5μmol/L C2 H5 OH}/S_{45μmol/L Petrol}≈4.0. It is a promising gas -sensing material.