Metals That Can Be Passivated
Passivation works on some steel grades–those commonly called stainless steel. They are called stainless because they stain (or rust) less than other grades, but they can still stain (rust). What passivation does is increase their resistance to staining (rusting).
In theory, this process can be applied to almost any metal. In practice, it is normally applied to stainless steel and titanium.