Effect of corrosion on the transfer impedance of zinc-coated steel enclosures

In this paper, the effect of corrosion on the degradation of electromagnetic interference (EMI) shielding enclosures in terms of transfer impedance is discussed. To provide a relationship between the transfer impedance and corrosion, an equivalent circuit model for gasketed EMI shielding barriers was developed and the transfer impedance of zinc-coated steel-plate enclosures at DC and 100 kHz frequency was measured. The results suggest a way of predicting transfer-impedance increase based on corrosion-induced resistance change.