Mini review on effect of coatings on the performance of magnetorheological materials

Abstract

Magnetorheological materials have attracted a great deal of interests nowadays due to its controllable mechanical properties upon the application of external magnetic field. Its ability to change its rheological properties in a split second has found its way in the applications that require absorption and isolation of vibration and noise. However, the problems with oxidation, sedimentation and aggregation of the magnetic particles hinder the optimum performance that can be utilised with this smart material. This includes the reduced performance of yield stress, shear stress, shear modulus and storage modulus and over a long operational period, will affect its magnetisation properties. Hence, there is a need to protect the magnetic particles with coating layer which can overcome these drawbacks. The main focus of this work is to present an overview on the aforementioned problems in MR materials that can be controlled by applying protective coating on the magnetic particles. Several works have reported the enhancement of performances such as oxidation resistance, interface between particles and the carrier medium as well as sedimentation stability by introducing coated magnetic particles in the MR materials.