Abstract

QUINONES, Jackeline; NG, Yolanda  and  ZAMBRANO, Alfredo. Películas gruesas de la_1-xsr_xfeo₃ como sensores de etanol. Rev. LatinAm. Metal. Mater. [online]. 2007, vol.27, n.1, pp.52-58. ISSN 0255-6952.

The sensitivity of a La_1-xSr_xFeO₃ (0.2 £ X £1) thick films towards ethanol has been studied. The powder samples were synthesized using the citrate method. The powders were screen printed on a-alumina pellets for sensitivity testing. The structural characterization was made by X ray powder diffraction. The sensitivity, was defined like the electrical gas resistance to the electrical air resistance ratio. The perovskite phase was verified in all samples. The samples La_1-xSr_xFeO₃ are orthorhombic when X < 1 and cubic when X = 1. This crystalline structure was not affected by the manufacturing process of the film. For all samples the temperature of maximum sensitivity was found to range between 150ºC and 200ºC. The lanthanum perovskites substituted with strontium (X < 1) show lower operation temperature than SrFeO₃ (X = 1), which has the highest operation temperature. The sensitivity of oxides increased potentially to the ethanol gas concentration.

Keywords : Ethanol sensors; Perovskites; Ceramic thick film; Synthesis.