MAGNETORHEOLOGICAL CHARACTERIZATION OF ORGANOCLAY ADDED CARBONYL-IRON SUSPENSIONS

초록

The flow behavior of carbonyl-iron (CI) suspensions containing submicron-size, additive particles was investigated in steady and oscillatory shear modes via precise control of magnetic field strength, and compared to the flow properties of simple CI-mineral oil (MO) suspensions without an additive. To enhance the dispersion stability and to examine submicron-size filler effect for the CI suspensions, organically modified montmorillonite (organoclay) was added to the CI-MO suspensions. The submicron-size particles inhibited the sedimentation of the CI particles, while maintaining the magneto-sensitive flow properties of the original CI-MO system. In addition, with the precision control of magnetic field strength, we examined the novel features of submicron-size particle filled CI suspensions, especially under weak magnetic field strengths, both in steady and oscillatory shear modes; a temporal decrease of steady shear viscosity in sweeping magnetic field strengths and a frequency dependent storage modulus at fixed magnetic field strength were observed.