【Basic Knowledge 13】What is local corrosion? Difference from general corrosion (quiz with prizes)
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What is local corrosion? What are its typical differences from general corrosion?
Local corrosion is a type of non-uniform corrosion, which involves the corrosion of certain areas on the metal surface. These include: pitting corrosion, crevice corrosion, galvanic corrosion, intergranular corrosion, stress corrosion, corrosion fatigue, wear corrosion, and selective corrosion. It is characterized by complexity, centralization, and suddenness. Difference from general corrosion: 1. It is concentrated in a specific area. 2. The anode and cathode can be distinguished. 3. Anode area < Cathode area. 4. Anode potential < Cathode potential. 5. Corrosion products do not provide protection for the metal.
General corrosion, also known as uniform corrosion, occurs in a relatively even manner across the metal surface. This type of corrosion does not easily lead to perforations. The corrosion product, iron oxide, can form across the entire metal surface; under certain conditions it provides protection, but it can also cause serious fouling. When corrosion occurs in a specific area on the metal surface, it is known as localized corrosion. This type of corrosion progresses very rapidly, and it can often cause the material to become corroded, perforated, or cracked at an early stage, making it highly hazardous.
Local corrosion refers to a situation where corrosion occurs in specific localized areas on the metal surface, with little to no corrosion occurring in the rest of the surface. Difference between local corrosion and general corrosion: concentrated in a specific area ； The anode and cathode can be distinguished ； Anode area < Cathode area ； Anode potential < Cathode potential ； Corrosion products do not provide protection for the metal.
Local corrosion is also known as non-uniform corrosion. Local cells are formed due to electrochemical heterogeneities (such as dissimilar metals, surface defects, concentration differences, stress concentrations, environmental heterogeneities, etc.). In localized corrosion, the cathode and anode can be distinguished from each other; the area ratio of the cathode to the anode is very large. The conjugate reactions at the cathode and anode occur in different areas. Localized corrosion takes place in specific locations and develops rapidly, whereas in general corrosion, the material corrodes and deteriorates quickly. General corrosion is also known as uniform corrosion, as the corrosion occurs fairly evenly across the metal surface. This type of corrosion does not easily cause perforation; the corrosion product is iron oxide
Local corrosion is a type of non-uniform corrosion, which involves the corrosion of certain areas on the metal surface. These include: pitting corrosion, crevice corrosion, galvanic corrosion, intergranular corrosion, stress corrosion, corrosion fatigue, wear corrosion, and selective corrosion. It is characterized by complexity, centralization, and suddenness. Difference from general corrosion: 1. It is concentrated in a specific area. 2. The anode and cathode can be distinguished. 3. Anode area < Cathode area. 4. Anode potential < Cathode potential. 5. Corrosion products do not provide protection for the metal.
What is local corrosion? What are its typical differences from general corrosion? Local corrosion: Corrosion occurs only in localized areas on the metal surface. Its harmfulness is much greater than that of uniform corrosion; it accounts for about 70% of all corrosion-related damages to chemical processing equipment. Moreover, it can be sudden and catastrophic, leading to accidents such as explosions and fires.
Corrosion of certain parts of the metal surface. Such as intergranular corrosion, subsurface corrosion, pitting corrosion, film-hole-type corrosion, etc. Although the weight loss is less than that of uniform corrosion, it poses a greater risk as it can lead to looseness or leakage in the metal structure.
Corrosion that occurs in certain localized areas on the surface, while other areas are not corroded or only suffer slight corrosion, is known as local corrosion. Difference from general corrosion: 1. It is concentrated in a specific area. 2. The anode and cathode can be distinguished. 3. Anode area < Cathode area. 4. Anode potential < Cathode potential. 5. Corrosion products do not provide protection for the metal.
Note: Also known as uneven corrosion. Corrosion of certain parts of the metal surface. Such as intergranular corrosion, subsurface corrosion, pitting corrosion, film-hole-type corrosion, etc. Although the weight loss is less than that of uniform corrosion, it poses a greater risk as it can lead to looseness or leakage in the metal structure.
Corrosion that occurs in certain localized areas on the surface, while other areas are not corroded or only suffer slight corrosion, is known as local corrosion. Difference from general corrosion: 1. It is concentrated in a specific area. 2. The anode and cathode can be distinguished. 3. Anode area < Cathode area. 4. Anode potential < Cathode potential. 5. Corrosion products do not provide protection for the metal.