What is electroplating? Zinc, nickel, chrome and gold explained

Electroplating for buyers: what each metal coating does, when to spec zinc vs nickel vs chrome, thickness, cost, and the hydrogen embrittlement trap.

Quick answer: Electroplating deposits a thin metal layer (zinc, nickel, chrome, tin, gold and more) onto a part by passing current through a plating bath. It adds corrosion resistance, wear resistance, conductivity or appearance depending on the metal. Zinc for cheap corrosion protection on steel fasteners, nickel and chrome for wear and looks, gold and tin for electrical contacts. Thickness is specified in microns or thousandths, and it is the number that decides whether the finish performs.

What each metal buys you

Different plating metals do different jobs. Pick by what the part actually needs, not by what looks premium.

Zinc plating is not stainless

This is the mistake that comes back as a warranty claim. Zinc plating is a sacrificial coating a few microns thick. A scratched or road-salted zinc-plated fastener rusts, because the protection is thin and gets consumed. For structural parts living outdoors in a salt province, hot-dip galvanize or specify stainless. Do not ask a few microns of electroplate to survive an Ontario winter it was never rated for.

The hydrogen embrittlement trap

High-strength steel above roughly HRC 40 that gets plated can absorb hydrogen during the process and crack later under load. The fix is a post-plate bake to relieve it, per ASTM B850. Skip the bake on a hardened bolt and you get a fastener that snaps weeks after install for no visible reason. If your part is hardened and plated, the bake is not optional, spec it.

Chrome is not always the answer

Decorative chrome on a part nobody looks at is money spent to impress a shelf. Hard chrome for wear on a hydraulic rod is worth every micron; bright chrome for looks on a hidden bracket is not. Match the plating to the function. For aluminum parts, anodizing is usually the better wear and corrosion finish than plating.

Cost and what to send

Plating is priced by process, metal, thickness and surface area, with batch minimums. For a ballpark by size and quantity, use the plating cost estimator. Send the base material, the plating and thickness spec, quantity, and any masking or bake requirement, then request quotes from Canadian platers.

FAQ

What is the cheapest plating for steel?

Zinc, by a wide margin. It is the standard low-cost corrosion coating for fasteners and hardware, but it is sacrificial and thin, so it is not a substitute for galvanizing or stainless on structural outdoor parts.

What is the difference between plating and anodizing?

Plating deposits a metal layer on top of the part; anodizing converts the surface of aluminum into an integral oxide. Plating works on steel and many metals; anodizing is for aluminum and titanium only.

Why does plated high-strength steel crack?

Hydrogen embrittlement. Plating can drive hydrogen into hardened steel, which cracks under load. A post-plate bake per ASTM B850 relieves it. Always spec the bake on hardened plated parts.

Is chrome plating bad for the environment?

Traditional hexavalent chrome is restricted under regulations like RoHS. Trivalent chrome and other alternatives exist. If compliance matters for your market, specify it, and choose a shop set up for it.

How thick should plating be?

It depends on the job: thin flash for solderability, thicker deposits for wear or corrosion. Thickness is specified in microns or thousandths on the drawing, and it is the number that determines performance, so do not leave it off.

Last reviewed: July 2026. Related reading: what is anodizing and powder coat vs paint.