Meaning
A chemical degradation process and subsequent electrical puncture occur when tarnish films formed on silver-plated contacts rupture under applied electrical stress. The mechanism of silver sulfide breakdown involves physical formation of insulating tarnish layers in sulfur-rich environments followed by dielectric breakdown under operating voltages. The degradation cycle halts when silver plating is replaced by tarnish-resistant noble metals or when operating environments remain free of atmospheric sulfur compounds.
Sulfidation Film Formation
Silver surfaces react readily with airborne hydrogen sulfide gas to produce soft, poorly conductive silver sulfide coatings. Prior to silver sulfide breakdown, the growing sulfide layer acts as an insulating barrier that disrupts low-voltage signal transmission across separable connectors.
Conduction Failure
Applied voltages exceeding the dielectric breakdown strength of thin sulfide films force localized electrical puncture, forming narrow conductive filaments. When silver sulfide breakdown occurs, contact resistance drops abruptly from high insulating levels back to low metallic values, causing erratic signal fluctuations. Repeated mechanical mating or thermal expansion breaks brittle sulfide films, generating non-linear contact interfaces that produce high passive intermodulation.
RF signal traces show intermittent noise spikes and power loss under sulfur exposure.
Environmental Testing
Accelerated environmental testing subjects silver-plated components to flowers-of-sulfur or mixed flowing gas chambers. Qualification procedures monitor contact resistance and intermodulation growth to establish time-to-failure curves under sulfur exposure. Engineering reports specify conformal coating requirements or alternative contact surface platings for sulfur-rich operating environments.
