The Effect of Orientation of Filler by Magnetic Field on the Resistivity and Adhesiveness of Electrically Conductive Adhesive
If the magnetic field acts on the electrically conductive adhesive containing a ferromagnetic metal filler in the process of curing, the filler is oriented and the conductivity of the adhesive is expected to be increased. In this paper, the effects of the orientation of filler on the electrical conductivity of the adhesive and the adhesive bond strength are investigated. Iron powder and silver-plated iron powder were used as a filler and epoxy adhesive was used as matrix resin.
The resistivity change with time in the curing process of the electrically conductive adhesive under magnetic field revealed some characteristic features. This is due to not only the orientation of the filler but also the change of the electrical resistance or other physical properties of epoxy matrix with the progress of curing. It was made clear that the alternating magnetic field was more effective than direct magnetic field on the increase of electrical conductivity of the electrically conductive adhesive.
The filler particles were hardly observed on the interface between adherend and adhesive. Hence the existence of the filler in the adhesive did not influence upon the bond strength of the adhesive to adherend.