DEMO — fictional range. Local brief only, NOT SENT. No personal data is collected or transmitted.
PLATING
The plating is the contact surface.
The metal underneath carries the current, but the surface is what touches the other half. Plating is chosen for resistance, wear and the environment, in that order.
- Gold, thin
- Low and stable resistance · the usual choice, and it wears through if thin
- Gold, thick
- For many mating cycles · the same surface, longer life, higher cost
- Tin
- Cheap and solderable · oxides form, and the oxides are resistive
- Tin over nickel
- A barrier under the tin · stops the tin diffusing into the base metal
- Nickel, shell only
- Corrosion protection on shells · not used as a contact surface
- Silver
- The lowest resistance · tarnishes, and the tarnish is resistive
Illustrative plating reference
| Plating | Typical use | How it fails |
|---|---|---|
| Gold 0.4 µm | Mated once, dry environment | Worn through at low cycle counts |
| Gold 0.8 µm | Repeated mating | Cost, if the cycles are not needed |
| Tin | Permanent joints | Oxide film raises resistance over time |
| Silver | High current, sealed | Tarnish in a sulphur-bearing atmosphere |
Why gold is specified by thickness rather than by presence.
Because it wears. A thin gold layer is a short life, and the failure is a rise in resistance rather than a visible defect, which makes it hard to attribute.
The one worth avoiding.
Gold on one half and tin on the other. The pair is a corrosion cell, and the tin side is what suffers.