Stabilization of magnetorheological fluid suspensions using a mixture of organoclays

This invention relates to magnetorheological fluids. A magnetorheological fluid formulation comprising magnetizable particles dispersed in a multi-component liquid vehicle comprising an organoclay stabilization mixture. At least one organoclay is selected for each liquid vehicle component, each organoclay having a surface chemistry that renders it preferentially compatible with the surface functionality of one of the liquid components relative to its compatibility to the remaining components whereby it is effective to stabilize, or gel, that component. A method of making an MR fluid is also provided in which liquid vehicle components are blended together, the organoclay mixture is added to the blend, and magnetizable particles are suspended therein, resulting in a stable MR fluid of suitable viscosity and yield stress.