Stainless steel passivation is a chemical process to remove free iron and contaminants from the surface of stainless steel. The stainless forms its own passive

Stainless steel passivation is a chemical process to remove free iron and contaminants from the surface of stainless steel. The stainless forms its own passive film upon contact with oxygen - it is not added. You make a good point about the surface primarily being chromium oxide.