【Corrosion Technology Edition】Daily Question 20170727: What is concentration cell corrosion?
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To increase the popularity of the Corrosion Technology section, foster communication among users, and enable mutual progress and improvement, the 【One Question per Day】 activity has been launched. Reward rules: 3 wealth points for replying, 10 wealth points for a correct answer. This topic is valid for two days; no scoring or rewards will be given after that. Term explanation: What is concentration cell corrosion? A corrosion cell is formed when a battery has different electrode potentials due to differences in the concentration of corrosive agents near the electrode surfaces. =============================== 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)
A corrosion cell formed by the potential difference caused by differences in the concentration of corrosive agents near the electrode surface.
Due to the varying oxygen concentrations in different parts of the steel, the natural potential (non-equilibrium potential) of the pipeline in the oxygen-poor areas is low; these areas act as the anode of corrosion cells. The rate of anodic dissolution in these areas is significantly higher than that on the remaining surfaces, resulting in corrosion.
Corrosion resulting from a concentration difference in oxygen due to varying oxygen concentrations in different areas, forming an oxygen concentration cell
When the boiler is shut down, water that remains in the boiler headers, drum, and the recessed areas of the furnace tubes results in a situation where the surface layer of water is in contact with the atmosphere, leading to a high concentration of dissolved oxygen, while the concentration of dissolved oxygen in deeper layers is relatively lower. This creates different electrode potentials on the same metal surface: areas with higher oxygen concentrations have a higher potential and act as cathodes, whereas areas with lower oxygen concentrations have a lower potential and act as anodes. This phenomenon leads to corrosion, which is what is commonly referred to as waterline corrosion. Since waterline corrosion is caused by a difference in oxygen concentration, this type of corrosion is referred to as oxygen concentration cell corrosion.
Corrosion occurs when different parts of the same metal come into contact with solutions of varying oxygen content, resulting in an oxygen concentration cell (also known as a non-uniform oxygenation cell).
A corrosion cell is formed when a battery has different electrode potentials due to differences in the concentration of corrosive agents near the electrode surfaces.
Corrosion resulting from the potential difference caused by differences in the concentration of corrosive agents near the electrode surface.
When the boiler is shut down, water that remains in the boiler headers, drum, and the recessed areas of the furnace tubes results in a situation where the surface layer of water is in contact with the atmosphere, leading to a high concentration of dissolved oxygen, while the concentration of dissolved oxygen in deeper layers is relatively lower. This creates different electrode potentials on the same metal surface: areas with higher oxygen concentrations have a higher potential and act as cathodes, whereas areas with lower oxygen concentrations have a lower potential and act as anodes. This phenomenon leads to corrosion, which is what is commonly referred to as waterline corrosion. Since waterline corrosion is caused by a difference in oxygen concentration, this type of corrosion is referred to as oxygen concentration cell corrosion.
Concentration cell corrosion is an electrochemical corrosion that occurs when different parts of the same metal come into contact with media of different concentrations or temperatures.