Chromium Electroplating

Chromium electroplating deposits a thin chromium layer for high wear resistance, low friction, and bright appearance, with thickness-driven dimensional impact and edge buildup.

Overview

Chromium electroplating (chrome plating) deposits metallic chromium onto a conductive substrate in an electrolytic bath. It’s used as hard chrome for wear/fretting resistance and reduced friction, or as decorative chrome over nickel for a bright, corrosion-resistant finish.

Choose it for shafts, rods, bores, and sealing surfaces that need improved hardness, scuff resistance, and controlled thickness that can be ground or honed after plating. It also works well for salvage builds: plating can restore worn dimensions before final machining.

Tradeoffs: thickness varies by geometry—edges and high current-density areas build up more, while deep recesses may plate thin. Masking and fixturing drive cost and lead time. Hydrogen embrittlement can be a risk on high-strength steels, so bake requirements should be called out. Environmental and regulatory controls can limit supplier options and increase cost, especially for traditional hexavalent processes.

Common Materials

  • Carbon steel
  • 4140 steel
  • 17-4 PH stainless steel
  • 304 stainless steel
  • Copper
  • Brass

Tolerances

±0.0005" to ±0.002" (on final dimensions after plating/grind)

Applications

  • Hydraulic cylinder rods
  • Piston rings and liners
  • Pump shafts and sleeves
  • Mold cores and cavities (wear surfaces)
  • Rollers and guide bars
  • Valve stems

When to Choose Chromium Electroplating

Choose chromium electroplating when the functional surface needs high wear resistance and low friction with a controllable, add-on thickness. It fits both new parts that will be finish-ground after plating and repair work where you need to build up worn diameters. Best results come from geometries that allow consistent current density and straightforward masking.

vs Anodizing

Choose chromium electroplating when you need a true metallic wear surface with very high hardness and the ability to build thickness for dimension restoration. It’s also a better fit for steels and copper alloys where anodizing isn’t applicable.

vs Powder Coating

Choose chromium electroplating when the coated surface is a precision wear or seal interface that can’t tolerate thick, soft films. Chrome provides a thinner, harder, lower-friction surface and can be post-ground to tight final size.

vs E-Coating

Choose chromium electroplating when wear, galling, and friction are primary drivers rather than uniform corrosion coverage. E-coat excels at thin, conformal paint-like coverage in cavities; chrome excels on exposed working surfaces where hardness matters.

vs Nickel Electroplating

Choose chromium electroplating when you need higher wear resistance and lower friction on sliding/rotating contact surfaces. Nickel is often better for uniform coverage and corrosion performance, while chrome is preferred for hard, durable working surfaces.

vs Physical Vapor Deposition (PVD)

Choose chromium electroplating when you need thicker build (including salvage/repair) and the option to grind or hone after deposition. PVD is typically thinner and line-of-sight, making it less suited for dimensional restoration or deep bores.

Design Considerations

  • Call out required chrome thickness range and whether dimensions are before plating or after finish grind/hone
  • Avoid sharp edges and knife corners; add small radii/chamfers to reduce edge buildup and burning
  • Minimize deep blind recesses and high-aspect-ratio features where current density drops and plating thins
  • Specify masking areas and allowable mask lines; unclear masking is a common quoting and yield risk
  • Identify high-strength steels and require hydrogen embrittlement relief bake parameters when applicable
  • Provide finish requirements (Ra before and after plating) and note any post-plate grinding direction/stock allowance