The Mechanism of Fretting Corrosion
When tin-plated connector contacts undergo minute vibrations (thermal expansion or mechanical shock), the thin tin oxide layer breaks and re-oxidizes repeatedly. Over months, this builds up a non-conductive black oxide debris layer, leading to sudden, intermittent signal loss.
When Gold Plating is Mandatory:
- Low Signal Voltages (< 5V, < 100mA): Insufficient electrical energy to puncture through tin oxide films.
- High Vibration Environments: Automotive under-hood wiring, industrial motor drives.
- High Mating Cycles: Beyond 30 to 50 insertions, tin rubs off to expose base brass.
For budget-sensitive projects, consider selective gold plating (gold on mating points, tin on solder tails) to achieve high reliability at lower cost.