Metal Finishing Guide
The right finish depends on the metal, the environment, and whether you need protection, appearance, hardness, or all three. Here’s how the four most common finishes compare — anodizing, powder coating, plating, and passivation — and when to choose each.
| Finish | Materials | Primary benefit | Thickness | Color |
|---|---|---|---|---|
| Anodizing | Aluminum (also titanium) | Hard, wear- & corrosion-resistant oxide layer | Thin (~5–25 µm; hardcoat thicker) | Dyeable (many colors); clear |
| Powder coating | Most metals | Durable, colorful protective polymer coat | Thick (~50–150 µm) | Huge color & texture range |
| Plating | Most metals | Corrosion (zinc), wear/hardness (hard chrome), or appearance/conductivity (nickel, chrome) | Thin (µm) | Metallic (zinc, nickel, chrome, etc.) |
| Passivation | Stainless steel only | Restores/strengthens the natural corrosion-resistant layer | None (no coating added) | No visual change |
Anodizing
Find shops →Electrically insulating; minimal dimensional change; integral to the part, won’t chip.
Powder coating
Find shops →Tough and economical; masks fine detail — keep off tight tolerances, threads, and bores.
Plating
Find shops →Pick the deposit for the goal: zinc = cheap corrosion protection, hard chrome = wear, nickel = build-up/appearance.
Passivation
Find shops →Chemical treatment (nitric/citric) that removes free iron; no dimensional change — common after machining stainless.
Need finishing done? Browse U.S. finishing & post-processing shops, or get a part quoted.
Find finishersFrequently asked questions
- Anodizing vs powder coating?
- Anodizing is an integral oxide layer on aluminum — thin, hard, won’t chip, and electrically insulating. Powder coating is a thick applied polymer that works on most metals and offers far more colors/textures, but it adds bulk and can mask fine features. Choose anodizing for hard, dimensionally-stable aluminum; powder for tough, colorful protection on steel and assemblies.
- Do I need passivation on stainless?
- Usually yes after machining. Cutting can smear free iron onto a stainless surface, which rusts. Passivation (a nitric or citric acid treatment) removes it and enhances the native chromium-oxide layer — with no coating or dimensional change.
- Which plating for corrosion vs wear?
- Zinc plating (often with a chromate or passivate top coat) is the economical choice for corrosion protection on steel. Hard chrome is for wear and hardness. Nickel is used for build-up, corrosion, and appearance. Match the deposit to the job.