Passivation Bath Purification

Passivation is a chemical cleaning process that removes free iron (as well as dirt and grease) from stainless steel parts. When correctly passivated, the metal surface will spontaneously form a passive metal oxide film that protects the surface from corrosion and rust. The resulting metal surface should appear clean and show no pitting, etching or frosting.

The two types of passivation — nitric and citric — are detailed in The American Society for Testing and Materials (ASTM) specification A967. The specification establishes bath chemistry volumes and temperatures, and the proportionate amount of exposure time for parts. It also provides various tests to validate the process.

Passivation Bath Purification is a contamination removal unit which helps in the elimination of Zinc and Iron contaminants from a Passivation bath.

Passivation Bath Purification baths are often contaminated by Zinc and Iron. Zinc arises due to the Zinc carryover from the previous Zinc coating and Iron contamination arises out of steel components fallen from jigs. Increased level of these contaminants in a passivation bath leads to inconsistent coating quality and increases the bath discharge frequency