Morphological study of silver corrosion in highly aggressive sulfur environments

A silicone coated power module, having silver conducting lines, showed severe corrosion, after prolonged use as part of an electronic device in a pig farm environment, where sulfur containing corrosive gasses are known to exist in high amounts. Permeation of sulfur gasses and humidity through the silicone coating to the interface has resulted in three corrosion types namely: uniform corrosion, conductive anodic filament type of Ag2S growth, and silver migration with subsequent formation of sulfur compounds. Detailed morphological investigation of new and corroded power modules was carried out, and possible theoretical explanation for various corrosion mechanisms has been attempted.

► Power module with silicone coating failed after use in rural environment.
► Despite coating, all silver surfaces were found to be highly corroded.
► Corrosion was attributed to permeation of sulfur containing gasses through coating.
► Three corrosion types were identified: uniform corrosion, creep corrosion and conductive anodic filament formation.