In industry, passivation is a process in which metal is treated in nitrite, nitrate, chromate or dichromate solution to form a chromate passivation film on the metal surface. Chromate treatment of aluminum and its alloys can lead to a chemical conversion film which is completely different from anodization. Its composition is as complex as that of zinc and cadmium chromium.

For stainless parts, acid wash and passivation processes often used together to remove the rust and form a more corrosion resistive layer. The passivation agent is a combination of nitric acid, hydrofluoric acid, potassium dichromate and sometime hydrofluoric acid. The process prolongs the rust-proof time of stainless steel in a high salinity environment.