Xiongbo Yang

Influence of Oleic and Lauric Acid on the Stability of Magnetorheological Fluids

In this paper, magnetorheological fluids (MRFs) based on micro-sized iron particles dispersed in silicone oil are presented. The iron particles are modified by adding different ratios of oleic acid and lauric acid as surfactants to the suspensions. Lauric acid was found to reduce the stability of the MRFs, and more lauric acid results in a higher rate of sedimentation. Further study showed that the formation and structure of lauric acid may result in the sedimentation of micrometer-sized particles. Meanwhile, the electro-resistance of MRF in this paper shows a decrease from beyond 6000 MΩ to 190 Ω with an increase in the external field from 0 mT to 400 mT.

Magnetic-field-tuned Insulator to Conductor Transition in Magnetorheological Suspension

Magnetorheological suspensions (MRSs) are smart materials that have the potential to revolutionize several industrial sectors because of their special rheological behaviors. In this paper, MRS, based on carbonyl iron (CI) microparticles that were dispersed in silicone oil with oleic acid, were prepared. We showed that the electroconductibility of MRS was significantly influenced by the intensity of the external magnetic field that was applied. The resistance value can vary from infinite to below 300 Ω after applying an external magnetic field. The results indicated that this MRS had the property of magnetic-field-tuned insulator to conductor transition. This system has potential applications in controllable MRS electrical devices.

An experimental study of magnetorheological fluids on electrical conductivity property

Magnetorheological fluids (MRFs) are smart materials made by base fluid, magnetizable particles, and stabilizer additives. A series of samples on varying of silicone oil, carbonyl iron particles, and oleic acid were prepared to investigate the stability of sedimentation and electrical conductivity property. Experimental results showed that the sample with mole ratio of oleic acid and carbonyl iron particles is two has the smallest saturation resistance, fastest response to external field, and the best stability of sedimentation. Further investigations suggested that low silicone oil viscosity and suitable amount carbonyl iron particles were desirable for enhance the electrical conductivity property of MRFs.