Both finishes protect aluminum. They look different, last differently, and cost differently. The decision usually comes down to three questions.
1. Does it need to be conductive?
Hardcoat anodize is an electrical insulator. Powder coat is also insulating but inconsistent. If you need conductivity through the surface, you need chromate conversion (alodine) or no coating at all.
2. How tight are the dimensional tolerances?
Type II anodize adds about 0.0004″ per surface. Type III hardcoat adds 0.001″ — and grows into the part by half that. Powder coat adds 0.002–0.005″ inconsistently. For tight-fit parts, anodize is the only practical option.
3. UV exposure?
Black anodize fades in direct sun within two years. Black powder with UV-stable resin holds color for ten. For outdoor enclosures, powder almost always wins.
Anodize for fit and electrical predictability. Powder for color and weather. Don’t mix them up.