Abstract

SYNTHESIS AND CHARACTERIZATION OF PURE AND MODIFIED CR2O3 THICK FILMS AS A LPG SENSOR

D. N. Suryawanshi, I. G. Pathan, G. P. Borse, K. D. Ahirrao and L. A. Patil*

Abstract

Thick films of pure chromium oxide (Cr2O3) were prepared by screenprintingtechnique. Pure (Cr2O3) thick films were almost insensitive toreducing gases. The surfaces of thick films of pure Cr2O3 weremodified by dipping them into 0.01 M aqueous solution of copperchloride (CuCl3) for different intervals of time followed by firing at5000C for 30 min. Firing results into the oxidation of CuCl3 additiveinto CuO. The characterizations and the gas sensing properties of pureand surface activated Cr2O3 thick films were investigated. The surfaceactivated Cr2O3 (60 min) thick films were observed to be sensitive to1000 ppm of LPG at 3000C. The grains of CuO dispersed around the grains of Cr2O3 wouldact as the barriers. Upon exposure of Liquefied Petroleum Gas (LPG), the barrier heightswould decrease greatly leading to drastic increase in conductance. The quick response andfast recovery are the main features of this sensor. The effects of microstructure and additiveconcentrations on the gas response, selectivity, response time and recovery time were studiedand discussed.

Keywords: CuO-activated Cr2O3, screen printing, thick film, LPG sensor, gas response.