Electrical conductivity of Ni ferrite nanofluids: An experimental study on the effects of temperature, volume fraction, and base fluid

This study investigates the electrical conductivity of NiFe₂O₄ nanofluids in water and ethylene glycol (EG) as base fluids, aiming to understand how varying volume fractions (φ= 0 %, 0.1 %, 0.25 %, 0.45 %, 0.7 %, and 1 %) and temperatures (20–70°C) influence electrical conductivity. NiFe₂O₄ nanoparticles were synthesized using the chemical co-precipitation method and characterized through X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and Energy Dispersive Spectroscopy (EDS). The results revealed that at 70°C, the electrical conductivity of NiFe₂O₄-water nanofluid increased by 1100 % within the volume fraction range of 0–1 %. For NiFe₂O₄-EG nanofluid, the increase in electrical conductivity was even more significant, reaching 1235 % within the same volume fraction range. Similarly, at a 1 % volume fraction within the temperature range of 20–70°C, the electrical conductivity of NiFe₂O₄-water nanofluid increased by 136 %, while for NiFe₂O₄-EG nanofluid, it was 370 %. These findings indicate that both temperature and volume fraction significantly enhance the electrical conductivity of the nanofluids, with a more pronounced effect observed in the NiFe₂O₄-EG nanofluid compared to the NiFe₂O₄-water nanofluid. The study validated Shen et al.'s model for electrical conductivity in nanofluids, contrasting with Maxwell's model. The novelty of this work lies in the comprehensive analysis of the electrical conductivity behavior of these nanofluids, which has not been extensively reported in the literature. These findings have potential applications in heat transfer enhancement and magnetic-targeted drug delivery.