A series of epoxy ferrite nanocomposites (EFNCs) was synthesised through dispersing ferrite nanoparticles (5.0 phr, parts per hundred of resin) into diglycidylether of bisphenol A (0.1 mol) in supercritical carbon dioxide at 85 AE 1 C, 1600 psi over 1 h followed by curing with triethylene tetramine (15 phr) at 40 AE 1 C. For this purpose, ferrite nanoparticles were synthesised through sizecontrolled precipitation method. The size of ferrite nanoparticles was calculated through XRD and further verified through transmission electron microscopy. The synthesised EFNCs were characterised through UV-Vis, FT-IR, laserinduced breakdown spectra, X-ray diffraction, scanning electron microscopy and vibrational sample magnetometry. The results showed that, with the decrease in size, the concentration of ferrite nanoparticle in EFNCs was increased ranging 3.843-4.042 phr. This resulted in a substantial increase in the compression, tensile, impact strength and Rockwell hardness of EFNCs. The effect of particle size on wear behaviour of EFNCs was investigated at various combinations of hydraulic end load ranging 1.0-3.0 bar and disc speed 230 rpm, which showed that a decrease in the size of ferrite nanoparticles imparts a remarkable reduction in wear volume over epoxy composite. All such EFNCs showed superparamagnetic behaviour with saturation magnetisation ranging 15.8-39.91 emu g À1 .