Study of Contact Failures Caused by Organic Contamination on Ag-Si Contacts

Effects of residual contamination that increases contact resistance with mechanical operation was investigated. Metal sealed switches with Ag-Si internally oxidized contacts were used. Contact surface was contaminated in varying degrees by dipping them into trichloroethylene (CHCICCI2) containing 0-3.0 vol% of paraffin lubricant. Contact were mechanically operated more than 10⁶times. Contact resistance increased gradually with operation, so long as the atmosphere contained oxygen. Contaminant was observed concentrated at the contact point. At the same time a method to evaluate surface organic contamination semiquantitatively was studied by Auger electron spectroscopy (AES).