Gold plating
Soft gold and hard gold-cobalt plating for connector pins and sockets, contacts and RF connector bodies. Plated to the thickness on your drawing, usually over a nickel barrier, and measured in-house by XRF.
Variants Soft gold · Hard gold
- Part
- Connector pins
- Finish
- Gold
Why gold
Gold does not oxidise or tarnish, so a gold contact surface keeps a low, stable contact resistance for years, even at low contact forces and low currents. That makes it the usual finish for signal contacts, connector pins and sockets, and RF connector parts.
Soft and hard gold
We plate both kinds of gold used in engineering:
| Kind | What it is | Typical use |
|---|---|---|
| Soft (pure) gold | 99.9% gold or better, soft | Contacts that are rarely mated, soldered or wire-bonded parts, RF surfaces |
| Hard gold | Gold-cobalt, about 99% gold and 1% cobalt, which makes it harder and more wear-resistant | Pins and sockets that are mated many times and need wear resistance |
If your drawing only says "gold plate", tell us how often the part is mated and we will suggest which to use.
Nickel underlayer
Gold is almost always plated over nickel on copper-alloy parts. The nickel stops copper from diffusing up into the gold, which would otherwise discolour it and raise contact resistance over time. It also seals the base metal under any pores in a thin gold layer. See nickel plating for the German nickel, a low-stress, ductile nickel, that we plate under gold.
Plating lines
Small parts such as pins and sockets are plated loose in barrel or vibratory lines, which handle large quantities and plate every surface. Larger or delicate parts are plated on racks, which also allows selective plating of contact areas. See gold plating on contacts and connector pins.
Thickness
Gold is expensive, so the thickness on the drawing matters. Very thin gold, often called flash gold, is porous and suits contacts that are mated a few times in clean conditions. Contacts that are mated often, or that work in humid or polluted air, need thicker gold. Selective plating, where only the contact area is gold plated, keeps cost down on larger parts.
Our XRF instrument measures up to three coating layers on a metal base in one reading, so the gold and the nickel underneath it are measured from the same spot.
What to put on your drawing or enquiry
- Base material and grade
- Gold thickness in µm, and where it is measured
- Nickel underlayer thickness
- Pure or hard gold, or the specification type and grade
- Areas to plate, if not the whole part
- The plating specification and revision, if you work to one
- Quantity per lot and expected yearly volume
Specifications
| Specification | What it covers |
|---|---|
| ASTM B488 | Electroplated gold for engineering use. Classifies gold by type (purity), hardness code and thickness class. |
| MIL-DTL-45204 | US military specification for electroplated gold, with types, grades and thickness classes. |
| ISO 27874 | International standard for gold and gold alloy coatings for electrical, electronic and engineering use. |
| IS 3266 | Indian Standard for electroplated gold coatings for general engineering use. |
Send the specification and revision with your drawing and we will confirm whether we can meet it.
Parts we have gold plated
Also consider
Email your drawing for a quote
Attach the drawing and include as much of this list as you can. The more you send, the fewer questions we need to ask before quoting.
- Drawing: PDF, DWG, DXF or STEP
- Base material and grade
- Finish, and thickness in µm
- Quantity per lot and yearly volume
- Areas to mask, if any
- Standard or customer specification