Meaning
Erosion of the protective metallic layer on connector pins happens during repeated insertion and withdrawal cycles. This hard gold plating surface wear exposes the nickel underplate or the base copper alloy to atmospheric oxygen. Hardening agents like cobalt or nickel are added to the gold to increase its resistance to abrasion.
Without these additives, pure gold would gall and smear easily due to its soft crystalline structure.
Friction Coefficient
Smooth surfaces with proper lubrication exhibit lower shear forces during the mating process. High friction leads to rapid material transfer.
Mechanical Endurance
Specifications for high-reliability connectors often require hundreds of mating cycles without revealing the underlying metal layers. This hard gold plating surface wear is quantified using porosity tests or nitric acid vapor exposure after mechanical cycling. The thickness of the plating, typically measured in millionths of an inch, determines the total life of the interface.
Porosity allows moisture to reach the base metal which creates insulating corrosion products. Engineers use salt spray tests to simulate real-world degradation. Once the gold layer is breached, the contact resistance rises substantially.
Lubricant Application
Lubricant application to the contact area reduces the rate of metal loss. These fluids fill the valleys of the surface roughness and prevent direct metal-to-metal welding. Proper application extends the service life of modular plug-in components.
