Preparation of magnetorheological fluid with excellent sedimentation stability

In order to prepare magnetorheological fluid with excellent sedimentation stability, various surfactants are applied to coat carbonyl iron powder. The prepared magnetorheological fluid shows excellent sedimentation stability when the surfactants are respectively sodium lauryl alcohol phosphate, compound sodium fatty acid methyl ester sulfonate, ethylene glycol monostearate and glyceride monostearate. Orthogonal tests are carried out for the optimal combination of surfactants and thixotropic agent. The experimental results show that the optimal combination of additives for MRF is 1.5 wt% of sodium lauryl alcohol phosphate, 1.0 wt% of compound MES, 1.5 wt% of ethylene glycol monostearate, 1.5 wt% of glycerol monostearate and 1.0 wt% of hydrophobic fumed silica. Magnetorheological fluid is prepared by the compound scheme, of which the viscosity is 1.09 Pa·s at 25.9°C and the sedimentation rate is 1.61% after one-week placement. The novel MRF is in excellent sedimentation stability and fluidity.