Gold or Tin Contact Plating - Which Should You Pick?
Whether gold or tin is the right contact plating depends on mating cycles, signal level and environment. This guide explains the differences in contact resistance, corrosion and wear, and warns against mixing gold and tin in the same connector.
View connectorsWhy is a contact plated at all?
The base material of a contact is usually copper or a copper alloy such as brass or bronze. These metals oxidise in air, and the resulting oxide layer conducts poorly. A layer of precious metal or tin protects the contact face and keeps the transfer resistance stable over its service life.
Beneath the top layer there is almost always a nickel barrier of 1 to 3 µm. It stops copper from diffusing into the gold or tin and degrading it from within. Without nickel the contact ages far more quickly.
- Base material: copper alloy spring contact.
- Barrier layer: 1‑3 µm nickel against diffusion.
- Top layer: gold (hard gold) or tin depending on use.
- Contact force: 0.5‑2 N per contact for a stable seat.
Gold or tin - where are the differences?
Gold is chemically almost inert, forms no insulating oxide and suits many mating cycles as well as low signal levels. Tin is much cheaper but grows a brittle oxide skin that has to be broken open with every insertion.
Tin suffers from fretting corrosion: with the tiniest relative movement from vibration or thermal cycling the oxide layer abrades and the resistance jumps up. Gold hardly knows this effect and stays stable even after many cycles.
How do I choose by cycles, level and environment?
Three questions lead to the right plating: how often is it mated, how small are the signals and how harsh is the environment? As soon as one of these axes is demanding, the choice shifts towards gold.
- Mating cycles: over 50 cycles or frequent servicing - gold.
- Signal level: low signal, sensors, RF and data bus - gold.
- Environment: humidity, salt, industrial air, vibration - gold.
- Fixed wiring, mated once, robust levels - tin is enough.
- Very high currents in the power range - often silver-plated contacts.
Frequently asked questions
How thick should the gold layer be?
For signal contacts, 0.2 to 0.8 µm of hard gold over nickel is common. Connectors rated for many cycles carry up to about 1.5 µm, while thinner flash gold below 0.1 µm only survives light duty.
Can I plug a gold pin into a tin socket?
No. The gold-tin material pairing forms a galvanic cell that accelerates corrosion on the tin side. Both mating partners should carry the same plating.
Why do tin contacts fail earlier under vibration?
Tiny relative movements trigger fretting corrosion: the brittle tin oxide abrades and the transfer resistance climbs. Gold is almost immune to this effect.
Is tin suitable for data lines?
For fast data and low-signal links gold is preferable because it secures a low and stable contact resistance. Tin fits fixed connections with higher levels better.
Gold or tin - we advise you
From gold-plated signal contacts to rugged tin connectors: we help you choose by mating cycles, signal level and environment.
Verified quality
Contacts with defined nickel barrier and layer thickness.
Matched pairing
Pin and socket supplied with the same plating.
Expert advice
Selection by cycles, level and environment.
Broad range
Gold and tin variants for many mating faces.