The effect of Mn_xCo_(1-x)Fe₂O₄ with x = 0, 0.25 and 0.5 as nanoparticles additives in magnethorheological fluid

This study focused on the effect of manganese substituted cobalt ferrite (Mn_xCo_1–xFe₂O₄) nanoparticles with different mole ratios (x = 0, 0.25 and 0.5) in magnetorheological fluids (MRF). The nanoparticles were synthesized using co-precipitation method. The irregularly–spherical form of the nanoparticles was observed/confirmed using a field emission scanning (FESEM) microscope. The vibrating sample magnetometer (VSM) was performed to analyze the effect of nanoparticles in MRF on their magnetic properties. The VSM test results show that the nanoparticles have a negative effect on the magnetic properties of MRF. The higher magnetic saturation of nanoparticles will reduce more magnetic saturation in MRF. This phenomenon shows that the direction of the magnetic field from the cobalt manganese ferrite has the opposite direction to MRF. It is also identified that the field-dependent rheological properties of MRF show that the addition of nanoparticles increases the yield stress of MRF results except for Mn_0.5Co_0.5Fe₂O₄ which leads to the reduction of the yield stress of MRF. (paper)