EXPERIMENTAL STUDY OF MR SUSPENSIONS OF CARBONYL IRON POWDERS WITH DIFFERENT PARTICLE SIZES

摘要: Magnetorheological suspensions (MRS) based on mixtures of two commercial carbonyl iron powders (BASF grades CL and SU) as magnetic phase hydrocarbon oil liquid were prepared. SU are both soft powders, but is a coarse powder, while fine one. The total mass fraction was 80% w/w each formulation. Hydrophilic fumed silica (5% Aerosil® 200) used to reduce the settling. mixing ratios were: 0%, 20%, 40%, 60%, 100%. A MRS, mixture 80%, showed considerable reduction plastic viscosity without field, in range 100 – 500 s-1, when compared MRS with just one powder. yield stress values under applied field H ~ 340 kA/m 18.1 kPa for 18.3 MRS's 20% 20.0 22.3 23.3 100%, respectively. For comparison, sample MRF-132LD (Lord Corp.) same conditions value 21.2 ± 0.6 kPa. On other hand, another an increment 33% normal force, relation prepared or above 150 kA/m. Therefore, different particle sizes can improve performance decreasing 'off' viscosity, increasing MR effect.