Fabrication of nanostructured magnesium ferrite polyhedrons and their applications in heat transfer management and gas/humidity sensors

摘要

In this paper we report the sol-gel synthesis of MgFe_2O_4 nanostructures of polyhedron morphology. X-ray diffraction (XRD) patterns revealed the presence of pure phase MgFe_2O_4 crystalline materials whereas Energy dispersive X-ray analysis (EDX) confirmed the presence of Mg, Fe and O in the compound. Scanning electron microscopy (SEM) image shows the porous scenery on the surface of the material whereas transmission electron microscopy (TEM) image displays polyhedron morphology of the particles. Sensor films fabricated utilizing these nanostructures were tested for gas/humidity sensing with notable success as the average sensitivity of the humidity sensor was found to be ～0.0237 MΩ/%RH over the entire range of humidity tested for and maximum % sensor response was found to be 27.19 corresponding to exposure of 4 vol% LPG. Minimum response and recovery times were found to be 79 and 60 s respectively for 0.5 vol% LPG. The magnesium ferrite nanoparticles were tested for heat transfer applications as ethylene glycol based nanofluid component. The result shows that the thermal conductivity of ethylene glycol nanofluid was significantly increased compared to pure ethylene glycol due to the presence of suspended MgFe_2O_4 nanoparticles.