Electromagnetorheological suspensions and inducted changes of their magnetic permeability and dielectric constant

Two groups of well-known suspensions are described in the early part of thi s article. Their viscosity and other properties can be changed by means of the electric and magnetic field. The main goal of this article is to presen t new types of suspensions with properties which can be changed by means of both the above mentioned fields. These suspensions consist of sodium chlor ide and magnetite particles or nickel-zinc ferrite dispersed in transformer oil. The method of producing these suspensions is described. Also given ar e the results from an analysis of their magnetic permeability and their die lectric constant induced changes. A comparison and discussion of the result s obtained are presented in the final part of the article. (C) 1999 America n Institute of Physics. [S0034-6748(99)02202-9].