B C Yadav
Articles written in Bulletin of Materials Science
Volume 34 Issue 4 July 2011 pp 689-698
This paper reports the synthesis of SnO2–CuO, SnO2–Fe2O3 and SnO2–SbO2 composites of nano oxides and comparative study of humidity sensing on their electrical resistances. CuO, Fe2O3 and SbO2 were added within base material SnO2 in the ratio 1 : 0.25, 1 : 0.50 and 1 : 1. Characterizations of materials were done using SEM and XRD. SEM images show the surface morphology and X-ray diffraction reveals the nanostructure of sensing materials. The pellets were annealed at 200, 400 and 600°C respectively for 3 h and after each step of annealing, observations were carried out. It was observed that as relative humidity (%RH) increases, there was decrease in the resistance of pellet for the entire range of RH. Results were found reproducible. SnO2–SbO2 shows maximum sensitivity for humidity (12 M𝛺/%RH) among other composites.
Volume 34 Issue 7 December 2011 pp 1639-1644
This paper reports the liquefied petroleum gas (LPG) sensing of titanium dioxide (Qualigens, India). Scanning electron micrographs and X-ray diffraction studies of samples were done. SEM shows that the material is porous and has grapes-like morphology before exposure to the LPG. XRD patterns reveal the crystalline nature of the material. The crystallites sizes of the TiO2 were found in the range of 30–75 nm. Variations in resistance with exposure of LPG to the sensing element were observed. The average sensitivity for different volume percentages of gas was estimated. The maximum value of average sensitivity was 1.7 for higher vol.% of LPG. Percentage sensor response (%SR) as a function of time was calculated and its maximum value was 45%. Response time of the sensor was 70 s. The sensor was quite sensitive to LPG and results were found reproducible.
Volume 42 | Issue 6
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