1) Give an anticorrosive coating 2) Make less reactive 
to coat metal with oxides to protect from corrosion
A process of surface treatment for neutralizing stainless steels. A n oxydizing solution, such as nitric acid is applied to the surface. This strengthens the normal protective film which helps in resisting corrosion. It also removes any foreign substance which might cause local corrosion.
To remove surface impurities from ferrous metals and alloys, e.g. prior to painting them
Type: Term Pronunciation: pas′i-vāt Definitions: 1. To render less activated, so as to diminish the activation of cells or cell surfaces.