Both add colour and corrosion protection, but they are built in completely different ways, and that difference decides which one is right for your part. Here is the head-to-head on colour, durability, dimensional growth, conductivity and cost, with a clear rule for choosing.
How each one is built
Anodizing grows a hard aluminium-oxide layer electrochemically into the metal. The finish is part of the surface, so it cannot chip or peel, and it follows the part exactly, even inside bores. It works on aluminium (and titanium) only.
Powder coating sprays a charged polymer powder onto the part, which is then baked into a continuous film on top of the metal. It is a true coating sitting on the surface, available on almost any metal, aluminium, steel, brass, in any colour and texture.
Side by side
| Anodizing | Powder coating | |
|---|---|---|
| How it's built | Oxide grown into the metal | Polymer film baked on top |
| Thickness | 3–5 µm (II) · 8–25 µm (III) | 60–120 µm (~2–5 mil) |
| Adds to each face | ~0.01 mm (Type III) | ~0.06–0.12 mm |
| Substrate | Aluminium / titanium only | Almost any metal (incl. steel) |
| Colour | Translucent metallic; RAL by dye; Type III dark only | Any RAL, opaque, gloss or texture |
| Hardness / wear | Hard, esp. Type III (~400–600 HV) | Tough but softer; can chip |
| Edges & bores | Even, including inside bores | Thin on edges, thick in recesses; not for deep bores/threads |
| Conductivity | Electrically insulating | Electrically insulating |
| Heat | Stable to high temperature | Limited by resin (~150–200 °C) |
| Cost | $$ | $$ |
| Best for | Precision aluminium, tight tolerance, wear, heat | Steel parts, bold colour/texture, thick outdoor protection |
When anodizing wins
Choose anodizing for aluminium parts that hold tight tolerances. It barely changes dimensions, follows bores and threads evenly, and adds real surface hardness for wear and sliding fits. It is the right call for precision housings, heat-exposed parts, and anything where a thin, dimensionally stable finish matters.
When powder coating wins
Choose powder coating for steel parts, bold or textured colour, and thick protective film. It coats steel (which cannot be anodized), offers an unlimited colour and texture range, and lays down a tough film that shrugs off weather and handling, ideal for brackets, frames and structural parts that live outdoors.
Three common mistakes
- Powder-coating a tight bore or thread — the thick film fills it. Anodize, or mask the feature.
- Expecting to anodize steel — anodizing is for aluminium and titanium only; on steel use powder coat or plating.
- Assuming the finish still conducts — both insulate. Mark any grounding or contact pads so we mask them.
Selection rule
Aluminium with tight tolerance, wear or heat → anodize. Steel, or any colour/texture and thick protection → powder coat. Needs to ground or shield → mask the contact either way.
