Influence of mineral silicon containing deburring media on contact resistance of fine silver rivets

The concentration of mineral silicon (SiO₂) on fine silver contacts subjected to deburring in an open tumbler and harperizing for specific time intervals was investigated in order to assess the factors contributing to low contact resistance in dry circuit applications. During arcing, a rather rapid surface degradation resulted at a contact pressure of 50 g (0.5 N). It was found that low contact resistance in dry circuit applications was achieved even when contact were severely contaminated with mineral silicon (SiO₂) are a contact pressure less than 50 g (0.5 N). Further reduction in static contact resistance was achieved by chemically etching contaminated rivets. The opposite results were obtained when contacts were subjected to a 12.5 V DC and 0.5 A load. Observations of low contact resistance in dry circuit applications and erratic millivolt drop during electrical switching are explained