Passivation resolves this issue by using acid solutions-commonly nitric acid or increasingly citric acid-to dissolve free iron and other contaminants from the surface. ve free iron from the surface. Slowly and naturally a passive layer develops on the surface of the steel as the chromium at the surface reacts with oxygen in the air to produce chromium oxide. If oxygen got to the iron, the iron would oxidize. What is Nitric Acid Passivation of Stainless Steel? Stainless steel derives its corrosion resistance from a microscopic, chemically inert layer of chromium oxide. Stainless steel is. Passivation is a chemical process that enhances stainless steel's corrosion resistance.