Zinc Electroplating

Zinc electroplating deposits a thin zinc layer on steel to provide sacrificial corrosion protection, with bright cosmetic finishes and good coverage on complex shapes.

Overview

Zinc electroplating is an electrolytic coating process that deposits zinc onto conductive substrates, most commonly carbon and alloy steels. The zinc acts as a sacrificial layer: it corrodes preferentially to protect the base metal. Shops often follow plating with chromate conversion (clear/blue, yellow, black) and optional sealers to tune corrosion performance and appearance.

Choose zinc plating for cost-effective corrosion resistance on hardware and stamped/machined steel parts, especially when you need thin coating build and minimal dimensional impact. It handles high volumes well and can produce bright, uniform cosmetic finishes.

Tradeoffs: coating thickness and coverage vary with geometry (edges build up, deep recesses can plate thin). Hydrogen embrittlement is a real risk for high-strength steels and requires baked relief per spec. Corrosion life depends heavily on thickness and post-treat; specify the exact thickness and chromate type rather than “zinc plated” only.

Common Materials

  • Carbon steel
  • Alloy steel
  • Spring steel
  • Stainless steel
  • Copper
  • Brass

Tolerances

±0.0002" to ±0.0005" thickness control (typical); dimensional change roughly equals coating thickness per surface

Applications

  • Automotive brackets and fasteners
  • Stamped steel clips and retainers
  • Industrial enclosures and panels
  • Machine screws, washers, and nuts
  • Hydraulic fittings and couplers
  • Electrical grounding hardware

When to Choose Zinc Electroplating

Use zinc electroplating for steel parts that need sacrificial corrosion protection with a thin, economical coating and a controlled cosmetic finish. It fits medium to high volumes and parts where light-to-moderate corrosion resistance is acceptable with the right thickness and chromate. It’s a strong choice when small dimensional change matters more than heavy-duty barrier performance.

vs Anodizing

Choose zinc electroplating when the substrate is steel and you need sacrificial corrosion protection. Anodizing is for aluminum/titanium and does not provide sacrificial protection for steel parts.

vs Powder Coating

Choose zinc electroplating when you need a thin coating that preserves threads, fits, and small features with minimal buildup. Powder coating gives thicker barrier protection and better cosmetic uniformity, but it can interfere with tight assemblies and internal threads.

vs E-Coating

Choose zinc electroplating when you need sacrificial protection and good conductivity on steel hardware and small parts. E-coat is a paint-like barrier with excellent coverage and uniform film build, but it won’t protect exposed steel the way zinc does if the coating is damaged.

vs Chromium Electroplating

Choose zinc electroplating when corrosion protection and low cost are the priority. Chromium plating targets wear resistance, hardness, and appearance; it’s typically more expensive and doesn’t provide sacrificial protection.

vs Nickel Electroplating

Choose zinc electroplating when you want sacrificial corrosion protection on steel and tolerance-friendly thin build. Nickel plating is a barrier coating with better wear/cosmetic options, but it’s not sacrificial and can accelerate corrosion at defects on steel.

Design Considerations

  • Call out zinc thickness (e.g., 5–12 µm) and chromate type/color plus sealer, not just “zinc plated.”
  • Flag high-strength steels (typically >~HRC 32 / 1000 MPa) and require hydrogen embrittlement relief bake per the applicable spec.
  • Avoid blind holes, deep narrow recesses, and sharp inside corners where current density is low and plating can be thin.
  • Mask bearing fits, precision bores, and ground surfaces; include clear mask drawings or 3D notes for quote accuracy.
  • Specify thread class after plating and consider oversize tapping/rolling if the thread fit is tight.
  • Define allowable cosmetic criteria (staining, rack marks, color variation) and the functional surfaces that matter most.