# Chromate Conversion (Alodine / Chem Film)

> Corrosion protection that stays conductive — the EMI-grounding finish for aluminum.

- Process group: Chemical Treatments
- HTML page: https://fabvector.com/finishes/chromate-conversion (Portuguese: https://fabvector.com/pt/finishes/chromate-conversion)

## Specifications

| Spec | Value |
|---|---|
| Coating thickness | 0.5–4 µm |
| Tolerance impact | Negligible (<4 µm) — no compensation needed; safe on finished tolerances, threads and EMI gasket faces. |
| Corrosion rating | 168 h salt spray (MIL-DTL-5541, Class 1A). |
| Appearance | Golden-iridescent (Class 1A) or nearly colorless (Class 3); thin enough that the machined texture shows through. |
| Applicable substrates | aluminum |

## Not suitable for

Wear surfaces (the film is soft and microns thin — it abrades off); decorative applications expecting uniform color (iridescence varies); long outdoor exposure without a paint topcoat; non-aluminum metals.

## Typical applications

- Avionics and electronics enclosures needing EMI grounding
- Aerospace aluminum hardware per MIL-DTL-5541
- Primer base under wet paint or powder coat