Effect of α-Fe2O3 on transformer cooling and application

Abstract

In the current paper, hematite (α Fe₂O₃) nanoparticles (NPs) were prepared by the chemical co-precipitation method. These synthesized nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Raman spectroscopy, and vibrating sample magnetometry (VSM). The XRD studies for the nanoparticles revealed rhombohedral symmetry with space group: R3c (167), and the particle size is about 33.34 nm. The morphological studies carried out by SEM indicated that these prepared samples have a spherical morphology with some porosity. The specific surface area of this sample was calculated by the Brunauer–Emmett–Teller (BET) technique. FTIR spectroscopy confirms the Fe–O and O–Fe–O vibrations corresponding to stretching at the expected positions (520 cm⁻¹) related to the structure. From Raman data, modes corresponding to α-Fe₂O₃ are seen. From DC magnetisation studies, the current sample shows ferrimagnetic behavior. In addition, the value of M_s is 1.027 and value of M_r is 322.787×10^–6. Further nanofluids of these nanoparticles with different concentrations of transformer oil were prepared. The performance of this nanofluid as a coolant in transformer oil was also studied. The 0.2 g/l concentration shows the maximum improvement in breakdown voltage. Hence, under optimal conditions, these ferrofluids can perform well for insulating purposes.