Gold Electroplating

Gold electroplating deposits a thin gold layer on conductive parts for low-contact-resistance surfaces, corrosion protection, and a stable, solderable finish.

Overview

Gold electroplating is an electrolytic process that deposits a controlled, thin layer of gold onto a conductive base metal, usually over a nickel (or palladium-nickel) barrier. It’s specified when you need consistently low contact resistance, excellent corrosion/tarnish resistance, reliable solderability/wire-bondability, or a decorative gold appearance with controlled thickness.

Choose it for electrical contact surfaces, RF/microwave hardware, and precision components where performance depends on surface chemistry and long-term stability. Tradeoffs are cost (gold and process control), thickness limits (typically microns, not a build-up coating), and sensitivity to base-metal diffusion and contamination—often requiring an underplate and tight cleaning/handling. Masking, racking/contact points, and thickness verification add lead time and affect which surfaces can be plated uniformly.

Common Materials

  • Copper
  • Brass
  • Phosphor bronze
  • Nickel
  • Stainless steel
  • Kovar

Tolerances

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Applications

  • Connector pins and sockets
  • RF waveguide and cavity surfaces
  • PCB edge fingers and pads
  • Relay and switch contacts
  • Semiconductor leadframes
  • Jewelry and decorative hardware

When to Choose Gold Electroplating

Specify gold electroplating when electrical contact performance, corrosion/tarnish resistance, or solderability/wire-bondability must stay stable over time. It fits best for parts where only selected functional areas need coating and the underlying substrate can be properly cleaned and underplated. It’s common in low to medium volumes where performance justifies precious-metal cost and added inspection.

vs Anodizing

Choose gold electroplating when you need a conductive, low-resistance surface on contact areas or RF paths. Anodizing is primarily for aluminum and usually produces an insulating oxide layer, which is the opposite of what you want for electrical contacts.

vs Powder Coating

Choose gold electroplating when coating thickness must stay very thin and controlled and the surface must remain conductive and solderable. Powder coating is thick, typically nonconductive, and better suited for general corrosion protection and cosmetics on larger areas.

vs E-Coating

Choose gold electroplating when the requirement is stable electrical performance at the surface (contact resistance, bondability) rather than broad corrosion coverage. E-coat is a paint-like polymer film; it’s generally insulating and not intended for precision contact interfaces.

vs Nickel Electroplating

Choose gold electroplating when you need low contact resistance and tarnish resistance in harsh environments or low-signal applications. Nickel is a common underplate and can provide hardness and barrier performance, but exposed nickel can oxidize and raise contact resistance over time.

vs Physical Vapor Deposition (PVD)

Choose gold electroplating when you need robust coverage on complex geometries, controlled thickness at practical cost, or industry-standard contact finishes. PVD can offer very clean, thin films, but line-of-sight deposition and part size/fixturing constraints often limit coverage on recessed features.

Design Considerations

  • Define plating thickness, type (hard vs soft), and the exact areas to be plated with clear masking callouts or drawings
  • Specify the underplate stack (e.g., nickel barrier) and any diffusion/barrier requirements to prevent base-metal migration
  • Avoid deep recesses, blind holes, and tight internal corners where current density and thickness uniformity are hard to control
  • Provide rack/contact point locations or allow nonfunctional witness areas where contact marks and thickness variation are acceptable
  • Call out post-plate requirements like heat treatment, bake, or pass/fail tests (adhesion, porosity, contact resistance) up front
  • Control surface finish and cleanliness before plating; roughness and oils drive porosity, poor adhesion, and cosmetic defects