Yes. Passivation is essentially to oxidize the surface of the metal to form a dense oxide film to protect the inside of the metal from oxidation. Since passivation is an oxidation reaction, it must be a chemical reaction.
Iron and aluminum are passivated when they encounter concentrated sulfuric acid. Passivation essentially forms a dense oxide protective film on the surface of the metal to prevent the internal metal from reacting with the acid.
The essence of metal passivation is that the metal is concentrated sulfuric acid and concentrated nitrateAcid and other oxidation, the surface of the formation of a dense oxide film, this oxide film is insoluble in concentrated sulfuric acid, concentrated nitric acid, because concentrated sulfuric acid, concentrated nitric acid ionization of hydrogen ions is relatively small. Oxidizers such as hypochlorous acid and potassium permanganate can passivate metals or alloys.
Passivation occurs when iron reacts with cold concentrated nitric acid, and the composition of the oxide obtained by passivation is complex, and the equation is generally not written.
During oxidation, concentrated nitric acid reacts with iron to form ferric ions and nitrogen at the same timeForming a dense oxide film. This layer of oxide film can effectively protect iron products from further corrosion. It is important to note that the products of the reaction of concentrated nitric acid with iron may vary from case to case.
Where Fe stands for iron, HNO3 stands for nitric acid, Fe (NO3) 2 stands for iron nitrate, H2O stands for water, and NO stands for nitric oxide. This reaction is a violent exothermic reaction, accompanied by the release of gas that produces nitrogen. In the laboratory, this reaction can be observed by mixing iron with concentrated nitric acid.
does not not react, will react Al 6HNO3 (concentration) =△=Al (NO3) 3 3NO2↑ 3H2O. However, aluminum will be passivated in cold concentrated nitric acid, forming an oxide film on the surface, preventing further reaction.
Chemical reaction equation: The chemical reaction equation of aluminum and concentrated nitric acid is Al 6HNO3 (concentrated) =Al (NO3) 3 3NO2↑ 3H2O (condition: heating). < / p > < p > Al +