Passivation is the process of forming a passive layer of chromium oxide on the surface of stainless steel to protect it from corrosion. This is done by adding a chemical that removes free iron and allows chromium oxide to form. The reference for passivation of stainless steel is ASTM A967. See the Critical Cleaning Procedures section of this guide for passivation tests.
CITRANOX and CITRAJET for passivation applications—safety, efficacy and ease of use
Citranox: Phosphate-free, acidic detergent cleaning and passivation
Citrajet: Low-foaming, phosphate-free, acidic detergent cleaning and passivation