Common anti-rust methods for metallic materials used in the automotive manufacturing industry include:
Altering the internal microstructure of metals.
For instance, manufacturing various corrosion-resistant alloys, such as adding chromium and nickel to ordinary steel to create stainless steel.
2. Coating Method
A protective wax coating is applied to the metal surface, isolating the metal products from surrounding corrosive agents, thereby preventing corrosion.
Apply anti-rust wax, paint, or cover with corrosion-resistant materials such as vitreous enamel plastics on the surface of steel. Alternatively, coat with vapor phase corrosion inhibitors, vapor phase corrosion oils, or wrap with vapor phase corrosion film materials.
(2) Applying metals such as zinc, tin, chrome, and nickel to the surface of steel through electroplating, hot dipping, or spraying methods to create a corrosion-resistant coating. These metals often oxidize to form a dense oxide layer.
The membrane prevents water and air from corroding the steel.
(3) A chemical method is employed to form a dense and stable oxide film on the surface of steel, such as creating a fine magnetite film on metal components and other steel products.
3. Treating the corrosive material to eliminate it, such as regularly cleaning metal equipment (using cleaners, neutral rust preventatives, and rust inhibitors), placing desiccants and vapor-phase rust inhibitors in precision instruments.
Products such as rust inhibitors and vapor phase corrosion-retarding fibers, which involve adding a small amount of corrosion retarding agent to the corrosive medium to slow down the rate of corrosion.
Rust lacks a dense structure. Water and oxygen can penetrate through rust, continuing to rust the iron beneath. To prevent rusting, a dense surface layer is necessary to shield against corrosion. The surface of stainless steel
A layer of unreactive chromium(III) oxide. Using magnesium, titanium, zinc, or aluminum also results in a dense, unreactive oxide layer.
Galvanizing is a common anti-rust treatment. It involves applying a layer of zinc to the object to be protected, either through electroplating or hot-dip galvanizing. There are many reasons to use zinc, including its low cost and good adhesion to iron. When zinc comes into contact with iron, they form a battery. As zinc is highly reactive, it acts as the anode in the battery and gets oxidized, thereby protecting the iron at the cathode of the battery from oxidation (i.e., cathodic protection).
In more corrosive environments (such as seawater), cadmium will be used in place of zinc. If the coating is damaged by external forces or processing near joints, seams, or holes, and cannot fully cover the protected object, the coating can only provide protection through anodic protection. In some advanced layers, in addition to zinc, aluminum is also added, which migrates to the damaged parts of the coating. Both aluminum and zinc oxide can protect metals more effectively.
