【Corrosion Technology Edition】Daily Question 20170720: What is local corrosion?
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To increase the popularity of the Corrosion Technology section, foster communication among users, and enable mutual progress and improvement, we have launched the 【One Question per Day】 activity. Reward rules: 3 wealth points for replying, 10 wealth points for correct answers. This topic is valid for two days; no scoring or rewards will be given after that. Term explanation: What is local corrosion? Local corrosion refers to the occurrence of corrosion confined to specific areas or parts of a structure, that is, localized damage due to corrosion on the metal surface exposed to corrosive agents within a very small area. ============================== Event Promotion: Petrochemical Zone – “Creative Ideas for Energy Saving” event (the second phase is in full swing) http://bbs.hcbbs.com/thread-1666758-1-1.html (Source: Haichuan Chemical Industry Forum) 2017 Coal Chemical Industry Event – “My Technical Upgrades” http://bbs.hcbbs.com/thread-1786290-1-1.html (Source: Haichuan Chemical Industry Forum)
Part of it has been corroded, causing some damage.
Heterogeneous 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 separate areas, with localized corrosion concentrating in specific locations and progressing rapidly, leading to rapid corrosion and destruction of the material.
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.
Local corrosion is a type of non-uniform corrosion, which occurs in 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 any protection for the metal.
This post was last edited by wangld on 2017-7-20 08:19. Local corrosion refers to the phenomenon of localized damage due to corrosion occurring in a small area of the metal surface that is exposed to corrosive agents, i.e., in specific regions or parts of the structure.
Local corrosion is a type of non-uniform corrosion, which occurs in 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 any protection for the metal.
Local corrosion: also known as non-uniform 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.
Local corrosion refers to the occurrence of corrosion confined to specific areas or parts of a structure, that is, localized damage due to corrosion on the metal surface exposed to corrosive agents within a very small area.
Also known as uneven 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 separate areas, with localized corrosion concentrating in specific locations and progressing rapidly, leading to rapid corrosion and destruction of the material.