Stainless Steel Passivation

Despite the already high corrosion resistance of stainless steel, some uses demand even more resistance. One of the key issues with corrosion (other than the corrosion itself) is that it is autocatalytic. This means that once the corrosion has started, even if the corrosion site is very small, it will continue to spread and at an ever increasing rate. Therefore, it is very important to prevent any kind of corrosion in the first place.

Stainless steel passivation works by removing any free iron (exposed iron on the surface of the part). This leaves a thin, passive layer usually comprised of chromium and nickel that was already present in the material. Since nickel and chromium are so corrosion resistant, this layer provides greater protection to the already resistant base metal.

Metal Finishings Limited, offers both nitric acid passivation and nitric/dichromate passivation. These are both industry standard. For large orders, we would be prepared to introduce other passivation processes such as citric acid passivation. Passivation is often used as a pretreatment for the application of dry film lubricants to stainless steel components.

Specifications/Standards

Our passivation processes conform to: