Investigation of physicochemical and magnetic properties of zinc ferrite (ZnFe2O4) with different ultrasonic power for enhancement of thermal conductivity of refrigeration oils

Abstract. Zinc ferrite (ZnFe2O4) nanoparticles have gained significant attention globally, particularly due to their superior chemical properties, magnetic properties, and heat transfer referring to their particle size. The sonochemical technique is one of the most applied methods to prepare zinc ferrite nanoparticles as it offers faster reaction and the ability to break large aggregates into smaller aggregates up to nanoscale. This research uses sonochemical method with power variations of 25%, 50%, and 75% to obtain zinc ferrite nanoparticles, zinc ferrite nanoparticles obtained are then analyzed for morphology, phase, crystallite size, functional groups and magnetic properties. Then the obtained zinc ferrite nanoparticles were synthesized using 0.3% Polyester Oil (POE), this method was employed to analyze the nanolubricant as a refrigerant fluid additive. The nanolubricant was characterized using thermal conductivity. The smallest crystal, 11.51 nm, was found in the sample with 50% power. The functional groups confirmed the presence of Fe-O and Zn-O cation bonds in the octahedral and tetrahedral regions. Magnetic properties shows that zinc ferrite resulting from power variation 25%, 50%, and 75% is superparamagnetic. The characterization results show that the obtained zinc ferrite can be used as a nanolubricant in refrigerant fluid.