Degradation of electroplated silver coatings under the influence of an electric arc

Abstract

Protective coatings of silver or less often of gold, platinum or palladium are applied to reduce effects of the arc action on contact surfaces. Their application involves a problem of selecting optimal coating thickness for that would be adequate for operating conditions of the switches and most of all for the cut-off current intensity. A method of scanning electron microscopy together with an x-ray microanalysis has been applied to investigate into degradation processes of protective silver coatings. Tests have been performed by Scanning Electron Microscope JSM-5610 LV with Energy Dispersive X-ray Spectrometer JED-2201 (JEOL, Japan).