Chromium Electroplating

Chromium electroplating deposits a hard, wear-resistant, decorative or functional chrome layer on metals for appearance, corrosion resistance, and low-friction surfaces.

Overview

Chromium electroplating, also called chrome plating, uses an electrolytic bath to deposit a thin chromium layer onto a metal substrate. It provides a bright, reflective finish, improved corrosion resistance (especially over nickel), and very high surface hardness with low friction. Chromium can be applied as decorative chrome (very thin over nickel/copper) or as hard chrome (thicker, functional layers for wear surfaces and dimensional restoration).

This process suits parts that see sliding contact, abrasive wear, or require a high-end cosmetic finish on metals like steel, stainless, copper alloys, and some aluminums with proper underplating. Tradeoffs include line-of-sight limitations, edge build-up, potential hydrogen embrittlement in high-strength steels, and significant environmental and regulatory controls for hexavalent chromium baths. Tight control of base machining and masking is needed, since plating will follow the existing surface condition and geometry rather than fix poor base finishes. For the right applications, chromium electroplating delivers long-life surfaces and premium appearance at moderate to high production volumes.

Common Materials

  • Low carbon steel
  • Stainless steel 304
  • Tool steel
  • Copper
  • Brass
  • Aluminum 6061

Tolerances

—

Applications

  • Hydraulic cylinder rods
  • Mold cores and cavities
  • Piston rings and engine components
  • Rollers and printing cylinders
  • Industrial shafts and bearing surfaces
  • Motorcycle and automotive trim parts

When to Choose Chromium Electroplating

Choose chromium electroplating for metal parts that need a very hard, wear-resistant, low-friction surface or a bright, mirror-like decorative finish. It fits best when the substrate can be fixtured for line-of-sight plating and when you can tolerate some dimensional variation from localized thickness build-up. It’s well-suited to medium-to-high volumes or recurring rebuild work on wear surfaces.

vs Anodizing

Pick chromium electroplating instead of anodizing when you need a conductive, metallic surface with very high hardness and a bright reflective finish on ferrous substrates. It’s also the better choice for rebuilding worn diameters and providing low-friction sliding surfaces that must not be porous like some thick anodic films.

vs Powder Coating

Choose chromium electroplating over powder coating when you need a thin, tightly controlled coating with high hardness and precise bearing or sealing surfaces. Chrome plating is better for wear-critical shafts and rods where thick, soft, polymer coatings would change fit or quickly wear through.

vs E-Coating

Use chromium electroplating instead of e-coating when the primary requirements are wear resistance, surface hardness, and cosmetic metallic appearance rather than broad-coverage corrosion protection on complex assemblies. Chrome works best on discrete, fixtured parts where a durable, high-end finish justifies higher per-part cost and stricter processing controls.

vs Nickel Electroplating

Select chromium electroplating over straight nickel when you need higher surface hardness, lower friction, and the classic blue-white chrome appearance. Many decorative systems use nickel as an underlayer, but the chromium topcoat adds superior wear resistance and a more scratch-resistant finish.

vs Physical Vapor Deposition (PVD)

Choose chromium electroplating over PVD when you need to build measurable thickness for wear life or dimensional restoration, rather than ultra-thin engineered films. Chrome plating also scales better for large parts like rods and rollers where PVD chamber size and fixturing can become limiting and costly.

Design Considerations

  • Define required chrome type (decorative vs hard) and specify target thickness range and critical surfaces on the drawing
  • Avoid sharp corners, edges, and deep recesses where current density will cause burning, thin coverage, or non-uniform build-up
  • Call out masking requirements for bearing fits, threads, and sealing surfaces that must not receive or must tightly control plating thickness
  • Provide base material hardness and heat-treatment condition; for high-strength steels, specify hydrogen relief baking requirements
  • Machine parts to final geometry accounting for expected chrome thickness where diameters, clearances, and fits are critical
  • Specify surface finish before plating; chrome will replicate the underlying finish and will not remove machining marks or waviness