Enhancement of the relative magnetic permeability of polymeric composites with hybrid particulate fillers

Abstract

Composites with high relative magnetic permeability values can be used in many industrial applications, especially if they can be shaped using conventional polymer-processing technologies. In this study, various hybrid composite systems (i.e., particles with differing aspect ratio, size, and magnetic permeability embedded into a polymeric binder) were prepared in an attempt to reach high relative permeability values without the use of high pressures or sintering. It was determined that an interaction effect between the different types of fillers exists and enhances the relative magnetic permeability value of the composite in relation to the use of single type of magnetic filler. Relative magnetic permeability values of over 100 were achieved. Such relative magnetic permeability values represent a significant increase in the magnetic permeability over available magnetic composites prepared using similar processing techniques. The significant gains in magnetic permeability were realized by altering the maximum packing fraction, and ultimately the percolation threshold of the composite, by using low and high aspect ratio particles simultaneously in the formulation of the magnetic composites. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 1371–1377, 1997