Nitric Acid and Citric Acid Passivation Treatments from Klein Plating Works

Stainless Steel is naturally corrosion resistant due to its chromium content, but many have witnessed stainless steel rusting due to not being properly treated. Klein Plating Works offers nitric acid passivation and citric acid passivation. Passivation is the process used to remove the contamination from the surface of stainless steel.

Per ASTM A-380, passivation is "the removal of exogenous iron or iron compounds from the surface of stainless steel by means of a chemical dissolution, most typically by a treatment with an acid solution that will remove the surface contamination, but will not significantly affect the stainless steel itself."

Parts must be cleaned and any scale removed prior to the immersion in the acidic passivation solution. Once the free iron and other contaminates are removed, the stainless steel will rapidly form a continuous layer of passive chromium oxide rendering the item inert and corrosion resistant.

Klein Plating Works performs passivation in accordance to:

• ASTM A-380
• ASTM A-967
• AMS 2700
• QQ-P-35

The experienced metal finishing staff at Klein Plating Works will also test the parts to determine if the passivation process was successful. The most common method and the one used at Klein Plating is the copper sulfate test. Parts are immersed in a solution of copper sulfate for a period of time, then rinsed and examined for any traces of pink copper. If there is no indication of copper on the surface than the process is considered successful and the parts are passivated. Contact us for additional information about metal passivation treatments.

*Please note that KPW no longer offers a sodium dichromate treatment due to environmental factors and its lack of necessity.