Humidity and Gas Sensitivity of NI and Co Ferrites pellets with nanoscale grain size at Room Temperature

Abstract

Ni and Co ferrite pellets were prepared by co-precipitation method at 100 oC as a reaction temperature and then sintered at 400 oC for the phase formation. The identified phase was confirmed by x-ray diffraction analysis in which all intensity peaks of Ni and Co ferrites were observed which clearly indicates that the single phase of inverse spinel ferrite. Surface morphology of pellet was studied by Scanning Electron Microscopy (SEM), which shows high reacting surface area due to small grain size ≈ 32 to 40 nm. The pellets were prepared as gas sensor elements. We have studied humidity sensing with Ni and Co ferrite in pellet form. Also with Ni and Co ferrite, sensing to NH4 and acetone gas has been studied. It has been found that the gas sensing for test gases is found to be in the order of humidity, NH4, acetone and Cl2. Here it is shown that CoFe2O4 acts as a good sensor as compared to NiFe2O4 especially for acetone and ammonia gases

Keywords

• precipitation method
• ray diffraction
• gas sensor