【Corrosion Technology Edition】Daily Question 20170714: What is electrochemical corrosion?
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To boost the popularity of the Corrosion Technology section, enhance communication among users, and promote mutual progress and improvement, we have launched the [Question of the 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 electrochemical corrosion? Electrochemical corrosion refers to the loss of metal that occurs as a result of electrochemical reactions between the metal and an electrolyte. In other words, corrosion of metal materials in a humid environment (an electrolyte solution) through electrode reactions is known as electrochemical corrosion. ============================== Promotion campaign: Petrochemical sector – “Creative Ideas for Energy Savings” campaign (the second phase is currently in progress) http://bbs.hcbbs.com/thread-1666758-1-1.html (Source: Haichuan Chemical Industry Forum) 2017 Coal Chemical Industry – “My Technical Upgrades” http://bbs.hcbbs.com/thread-1786290-1-1.html (Source: Haichuan Chemical Industry Forum)
Corrosion occurs when a metal material comes into contact with an electrolyte solution, as a result of electrode reactions. Electrochemical corrosion is a type of redox reaction; in this reaction, the metal loses electrons and gets oxidized. This process is known as the anodic reaction, and the products of this reaction are metal ions that enter the medium, or metal oxides (or insoluble metal salts) that form on the surface of the metal； The substances in the medium gain electrons from the metal surface and are reduced; this reaction process is known as the cathodic reaction process. In the cathodic reaction process, the substances that gain electrons and are reduced are commonly referred to as depolarizers. During uniform corrosion, there is no significant difference in the probability of occurrence of anodic and cathodic reactions at various points on the metal surface, and the locations where these two types of reactions take place keep changing randomly. If certain areas on the metal surface primarily undergo anodic reactions, while other areas primarily undergo cathodic reactions, then the former are called anodic zones and the latter cathodic zones; these anodic and cathodic zones together form a corrosion cell. It is the anodic reactions that directly cause damage to metal materials. Therefore, an external power source is often used, or wires are employed to connect the metal to be protected with another metal having a lower electrode potential, so that corrosion occurs on the metal with the lower potential.
Corrosion that occurs when a metal material comes into contact with an electrolyte solution, as a result of electrode reactions
When an impure metal comes into contact with an electrolyte solution, a galvanic cell reaction occurs; the more reactive metal loses electrons and is oxidized. This type of corrosion is known as electrochemical corrosion.
When an impure metal (or alloy) comes into contact with an electrolyte solution, a galvanic cell reaction occurs; the more reactive metal loses electrons and gets oxidized. This type of corrosion is known as electrochemical corrosion
Corrosion that results from electrochemical reactions between metals and media involves an anode and a cathode region during the corrosion process, with electric current flowing through the metal over a certain distance; this applies to the corrosion of metals in various dielectric solutions such as seawater, acids, bases, salt solutions, and humid air.
Electrochemical corrosion occurs when a metal and an electrolyte form two electrodes, creating a corrosion cell.
Corrosion that occurs when a metal material comes into contact with an electrolyte solution, as a result of electrode reactions. Electrochemical corrosion reaction is a redox reaction. In the reaction, the metal loses electrons and is oxidized; this reaction process is known as the anodic reaction. The products of this reaction are metal ions that enter the medium, or metal oxides (or insoluble metal salts) that cover the surface of the metal ； The substances in the medium acquire electrons from the metal surface and are reduced; this reaction process is known as the cathodic reaction process. In the cathodic reaction process, the substances that gain electrons and are reduced are commonly referred to as depolarizers.
Electrochemical corrosion: Iron and oxygen form two electrodes, creating a corrosion cell
Corrosion that occurs when a metal material comes into contact with an electrolyte solution, as a result of electrode reactions. Electrochemical corrosion reaction is a redox reaction. In the reaction, the metal loses electrons and is oxidized; this reaction process is known as the anodic reaction. The products of this reaction are metal ions that enter the medium, or metal oxides (or insoluble metal salts) that cover the surface of the metal ； The substances in the medium acquire electrons from the metal surface and are reduced; this reaction process is known as the cathodic reaction process. In the cathodic reaction process, the substances that gain electrons and are reduced are commonly referred to as depolarizers. During uniform corrosion, there is no significant difference in the probability of anodic and cathodic reactions occurring at various locations on the metal surface; the surface areas where these two types of reactions take place keep changing randomly. If certain areas on the metal surface undergo primarily anodic reactions, while the remaining areas undergo primarily cathodic reactions, then the former are referred to as anodic regions and the latter as cathodic regions; the anodic and cathodic regions together form a corrosion cell. It is the anodic reaction that directly causes damage to metal materials; therefore, an external power source is often used, or wires are employed to connect the metal to be protected with another metal having a lower electrode potential, so that corrosion occurs on the metal with the lower potential.
Corrosion that occurs when a metal material comes into contact with an electrolyte solution, as a result of electrode reactions. The electrochemical corrosion reaction is a redox reaction