Tin Electroplating

Tin electroplating deposits a thin, solderable tin layer on conductive parts for corrosion protection, low contact resistance, and improved electrical performance.

Overview

Tin electroplating is an electrolytic process that deposits a controlled tin layer onto conductive substrates (commonly copper alloys and steels). It’s used to improve solderability, reduce contact resistance, and add mild-to-moderate corrosion protection, often as a bright decorative finish or a matte functional finish.

Choose tin plating for electrical connectors, terminals, busbars, and hardware that must solder consistently or maintain stable conductivity in storage and service. Key tradeoffs: tin is relatively soft and can wear or gall under sliding contact; thickness uniformity depends on geometry (edges build, recesses starve); and hydrogen embrittlement risk exists on high-strength steels unless properly baked. For long-term reliability, specify surface prep, thickness, post-plate passivation, and any whisker-mitigation requirements (matte tin, controlled chemistry, or reflow/anneal when applicable).

Common Materials

  • Copper
  • Brass
  • Phosphor bronze
  • Steel
  • Stainless steel
  • Beryllium copper

Tolerances

±0.0002" to ±0.0005" (plated thickness control; geometry-dependent)

Applications

  • Electrical connectors and contacts
  • Crimp terminals and lugs
  • Busbars and grounding straps
  • Fasteners for corrosive storage environments
  • Stamped leadframes for electronics
  • Shield cans and EMI hardware

When to Choose Tin Electroplating

Tin electroplating fits parts that need reliable solderability and low contact resistance on conductive substrates, especially stamped and formed components. It works well for medium to high volumes where consistent appearance and thickness control are required. It’s a good choice when the part will see handling, storage, and moderate corrosion exposure without heavy abrasion.

vs Anodizing

Choose tin electroplating when you need a solderable, highly conductive surface on copper alloys or steel. Anodizing is limited to aluminum and creates an insulating oxide layer, which is usually undesirable for electrical contacts.

vs Powder Coating

Choose tin electroplating when you need a thin metallic coating that maintains electrical conductivity and fits tight assembly interfaces. Powder coating is thicker, nonconductive, and better suited for cosmetic and general corrosion protection on larger parts.

vs E-Coating

Choose tin electroplating when electrical performance and solderability drive the requirements and coating thickness must be tightly controlled in the low-micron range. E-coat is primarily a uniform, paint-like corrosion barrier and typically insulates the surface.

vs Nickel Electroplating

Choose tin electroplating when solderability and low contact resistance are the priority and you want a softer, more solder-friendly finish. Nickel is harder and more wear resistant, but can complicate soldering unless paired with a suitable topcoat.

vs Zinc Electroplating

Choose tin electroplating when the part is an electrical interface or will be soldered. Zinc is a cost-effective corrosion coating for steel, but it’s not a preferred finish for low-resistance contacts and consistent solderability.

Design Considerations

  • Specify tin thickness in microns or inches and define measurement locations; thickness will build on edges and starve in recesses
  • Avoid deep blind holes, tight crevices, and shielded recesses where current density is low and coverage is inconsistent
  • Call out pre-plate requirements (degrease, activation, strike layer if needed) based on substrate and forming oils
  • For high-strength steels, specify hydrogen embrittlement relief baking requirements and timing after plating
  • Define solderability and storage requirements (matte vs bright, passivation/topcoat, whisker mitigation if applicable)
  • Mask or plug critical threads, bearing surfaces, or press-fit diameters to control final fit and prevent buildup where it matters