Passivation: Is it Really Necessary?

It has been traditionally thought that passivation is the standard method of cleaning stainless steel; when in fact passivation is not a cleaning process at all. The passivation process removes any residual carbon from the surface of the part by the use of nitric or citric acid. The acid dissolves the surface imperfections, such as embedded tool steel or other free iron particles. However, the sole purpose of passivation is to remove embedded iron; not to clean the part. Passivation will not remove any oils or other non-ferrous contaminates.