Nanocrystalline porous nickel ferrite ceramics for humidity sensing applications

Abstract

© 2019 IEEE. Over the last two decade, considerable interest has been received to synthesize novel ceramic nanomaterials with high humidity sensitivity characteristics for the fabrication of low-cost, fast and stable humidity sensors. This paper reports the preliminary results of humidity sensing properties of the nanocrystalline porous nickel ferrite ceramics fabricated by a conventional sintering of ultrafine nanopowders, which were successfully synthesized by soft mechanochemical processing. By using SEM and X-ray diffraction analyzes, the structural characteristics (average size of crystallites, density and porosity) of prepared NiFe2O4 ceramics were determined. At room temperature, this sensing material showed a linear response of impedance change within the wide relative humidity range from 15% to 85% at frequency of 2.5 kHz. Furthermore, the response time (adsorption process) of 26 s and the recovery time (desorption process) of 43 s have been obtained for this porous ceramic sensing material. Also, relatively small hysteresis, good repeatability and stability were also observed.