As a result of the manufacturing process, the surface of stainless steel parts contains small iron particles and unwanted oxides. During Nitric Acid Passivation these particles are dissolved by immersing the component in a solution of nitric acid, which cleans the parts by dissolving the free iron and making the surface less chemically reactive. Stainless steel that has been through nitric acid passivation has a hard non-reactive film that inhibits further corrosion. PTI offers both type two and type six methods. Nitric Acid Passivation also readies parts for other treatments including plating or painting.