Failure Mechanism of Gold-Plated Contacts in Mobile Phones Under Dust Contamination Jointing With Micromotion Condition

Serious environmental pollution degraded the reliability of gold-plated connectors in many-handed terminals. It was found that gold-plated contacts disassembled from failed mobile phones were tarnished and worn out. The main compositions of the contaminants on the failed contacts were dust particles, organic compounds, and worn contact materials with their oxide. The micromotion between contacts abrasively wore the contacts with the dust particles and organic compounds. Contact resistance on the tarnished contacts increased with the thickness of contaminants on the contacts. The combined effects of dust particles, organic compounds, and micromotion on the electrical behaviors of the gold-plated contacts were simulated and studied by adapting a fretting simulation system. The hard particles caused seriously abrasive wear of gold plating and quickly formed fretting corrosion to shorten the contact life. Tiny content of organic compounds supplied certain adhesion function of dust particles, which made it easy for the dust particles to insert the contact interfaces. The contaminants and wear debris with their oxide formed complexly tarnished morphology under micromotion conditions, which finally caused contact failure.