Influence of particles size and concentration of carbonyl iron powder on magnetorheological properties of silicone rubber-based magnetorheological elastomer

In this study, the anisotropic magnetorheological elastomer(MRE) was prepared by mixing two-component room temperature vulcanized(RTV) silicone rubber, carbonyl iron powder particles and dimethyl silicone oil uniformly, then heated and solidified under 500 mT magnetic field intensity. Five types of magnetic particles with different concentrations of 20%, 30%, 40%, 50%, 60% and five different sizes of 1.7, 2.8, 3.9, 4.6, 7.2 μm, were used to investigate the effects of the concentrations and sizes of the magnetic particles on the microstructure, mechanical properties and the magnetorheological effect (MR-effect) of anisotropic MREs. The results obtained from this study showed that the MR-effect has a significant dependence on the concentrations and particle sizes of the magnetic particles. It increased with the increase of the particle concentrations, and the high particle concentration makes the MRE have a high magnetostrictive modulus and MR-effect. Nevertheless, with the increase of the particle sizes, the MR-effect showed a trend of strengthening firstly and then weakening, there is an optimal particle size of 4.6 μm, at this size, the MR-effect is the most significant.