# Passivation

> Chemical hygiene for stainless: strips embedded iron so the steel can be as stainless as advertised.

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

## Specifications

| Spec | Value |
|---|---|
| Coating thickness | No coating — a sub-0.1 µm passive chromium-oxide layer is chemically rebuilt; embedded free iron is dissolved. |
| Tolerance impact | No dimensional change — all drawing tolerances apply unchanged. Safe on finished precision features, threads and sealing faces. |
| Corrosion rating | Restores the alloy’s intrinsic corrosion resistance (verified per ASTM A967 copper-sulfate or salt-spray test); adds nothing beyond it. |
| Appearance | No visible change — the part simply arrives cleaner. |
| Applicable substrates | stainless-steel, titanium |

## Not suitable for

Carbon and alloy steels (the chemistry does nothing for them — they need plating or coating); rescuing an under-specified alloy (passivated 304 still fails in chloride service where 316L is required); parts needing measurable smoothing or brightening (that is electropolishing).

## Typical applications

- Medical and surgical components (specified by default)
- Food and beverage contact parts
- Marine stainless hardware
- Aerospace fasteners and fittings