EMI shielding of conductive gaskets in corrosive environments

The environments were selected to simulate a controlled indoor environment; a temperate outdoor environment; and shipboard conditions. The gasket shielding performance was measured using the surface transfer impedance method. The results indicate that the spiral type gaskets perform best, both in terms of initial performance, and resistance of degradation with corrosion. The O-ring type elastomeric gaskets exhibited the worst degradation with weathering, probably due more to the degradation of its initially superior joint geometry. The flat cut-type elastomeric gaskets performed the worst in terms of initial performance. Oriented arrays of wire and knitted wire mesh types were also studied, and they showed similar performance, midway between that of the spiral and the elastomeric gaskets. The results of the experiments indicate that the oriented array type may have a problem with crevice corrosion effects. The benefits and costs associated with integral environmental seals were also studied.<>