There are various forms of metal corrosion, which can be divided into uniform corrosion and localized corrosion. The schematic diagram of the main corrosion forms is shown in Figure 1-1.
The corrosion effect of uniform corrosion occurs uniformly on the entire metal surface, and gradually corrodes the metal on the plane and reduces its various properties. Uniform corrosion without obvious corrosion depth, for example, the surface of steel is rusted, and the surface of zinc and aluminum is covered with white rust.
Localized corrosion can be subdivided into various forms of corrosion, mainly pitting corrosion, galvanic corrosion, crevice corrosion, erosion corrosion, selective corrosion, stress corrosion cracking, intergranular corrosion and corrosion fatigue. Localized corrosion is an important form of corrosion of metal components and equipment. Although the total amount of metal loss is not large, severe localized corrosion often leads to sudden damage to equipment, resulting in huge economic losses, and sometimes even disasters. sex accident.
