An experimental study on stability and rheological properties of magnetorheological fluid using iron nanoparticle core-shell structured by cellulose

In this study, silicone oil as the base fluid and carbonyl iron powder with the average particle size of 2.7 mu m as the disperse phase was used for magnetorheological fluid production. Nano-magnetic iron oxide particles are prepared using co-precipitation method. For identification and determination of structures of iron nanoparticle core-shell with cellulose, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed. Stretching of Fe-O bond originated from Fe3O4 group is observed at wavenumber of 660-550cm(-1). FTIR spectrum of Fe3O4 at cellulose nanoparticle shows unsymmetrical bond stretching at wavenumber of 1160cm(-1) which corresponds to the C-O-C bond. The existence of six peaks in XRD diffraction pattern of cellulose-covered nanoparticles proves the existence of Fe3O4. The morphology analysis of cellulose-covered Fe3O4 using SEM images showed a sponge-like structure as a result of coverage of Fe3O4 with cellulose. The effect of the Fe3O4 at cellulose nanoparticles and cellulose on the stability of fluid has been studied. It was observed that the sample containing 1% of Fe3O4 at cellulose nanoparticle alongside 3% cellulose stabilizer agent proved to be a very stable fluid. Viscosity and shear stress in different magnetic fields for this fluid at 25 degrees C was studied. Finally, Hershel-Bulkley model for estimation of yield stress at different magnetic fields was used. Results indicate an increase in yield stress in various magnetic fields by having a slope of 2 at the start, which later changes to 1.5 and becomes constant at strong magnetic fields.