Corrosion Resistance of Cu-Ni-Stainless Steel Multilayers for EMI Shielding Materials

摘要

The metallic coatings for electromagnetic interference (EMI) shielding must have a low electric resistance for effective electromagnetic wave shielding as well as good corrosion resistance to guarantee reliability of the electronic devices. Normally, the metallic coatings for EMI shielding consist of conductive layer, corrosion resistance layer and buffer layer. As the corrosion induced the delamination of coating layer, it could not function of EMI shielding. Therefore, in this paper, the effect of the stainless steel layer on the corrosion resistance was investigated. Several metals were deposited onto polycarbonate by RF magnetron sputtering. The structural characteristics of the film were investigated by means of X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The electrochemical properties were examined by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in 3.5 wt. percent NaCl solution. The results obtained from potentiodynamic polarization and EIS showed that 2205 stainless steel of upper layer had the better protective efficiency than 310S stainless steel.