Papers by Author: V.K. Aswal

Abstract: A magnetorheological fluid (MR), a suspension of micron-sized magnetic particles in a carrier fluid, has vast applications in the field of vibration dampers, seismic vibration dampers, shock absorbers, clutches, break system, vehicle suspensions, seat suspensions, Robotics, design of buildings and bridges etc. The biggest issue in MR fluid is the settling of particles under gravity. To overcome this, one of the approaches is to mix micron size particles in a magnetic fluid (MF) known as Nano-MRF. In the present paper, we report a technique to synthesis Nano-MRF suspension having high stability under gravitation as well as magnetic field. X-ray diffraction (XRD) and dynamic light scattering are used to characterize the solid/liquid system. Magnetic and Magnetorheological properties are studied and results indicate that: instead of decreasing stress with increasing temperature we have observed an increase until 40°C and thereafter, it decreases. This is explained based on, inter and intra particles/chain interaction as well as synergetic effect between small and large sized magnetic dispersion.

Abstract: Magnetite and Co ferrite particles were synthesized with control of particle size distribution via non-aqueous route. The XRD pattern shows the formation of single phase spinel structure with the particle size of 96 Å and 80 Å respectively for magnetite and cobalt ferrite. TEM image of the same shows the particles are nearly spherical with the size matches with that obtained from X-ray and the size distribution is less than 5%. Magnetic measurement also shows the particles of uniform size with high value of saturation magnetization at room temperature compared to that obtained by other route. SANS study confirms our results of monodispersed particles with spherical shape.