Metal anodic protection method
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One method of preventing corrosion in metal materials is electrochemical protection, which is divided into cathodic protection and anodic protection. In cathodic protection methods, there is: 1. Using an external current to make the metal that needs protection act as the cathode ； 2. Sacrificial anode cathodic protection method. Anodic protection involves connecting the metal component to be protected to the positive pole of an external direct current power supply, thereby polarizing the metal anode to a certain potential in the electrolyte solution and bringing it into a stable passive state. This prevents corrosion in the solution, significantly reducing the corrosion rate and thus protecting the equipment. The question is: what exactly is the “passive state” in the anodic protection method? I’m not very clear about what that entails; thank you for your guidance!
This is the theory of anodic passivation: after a metal is passivated, its potential shifts in the positive direction.
There is also the passivation theory, specifically the self-passivation theory; the original poster can take a look at books on metal corrosion
The polarization curve of metals with sluggish behavior shows that as the potential increases, the current density does not change significantly. In other words, in an electrolyte solution, when the metal anode is polarized to a certain potential that falls within the passivation range, the corrosion current density of the metal becomes relatively low; as a result, the corrosion rate decreases, thereby protecting the metal.
This post was last edited by lb594287163 on 2010-12-22 23:08. The polarization curve of metals with sluggish behavior shows that, when an external current flows through the circuit, the current density does not change significantly as the electrode potential increases. In other words, in an electrolyte solution, when the metal anode is polarized to a certain potential that falls within the passivation range, the corrosion current density of the metal becomes relatively low, meaning the corrosion rate is reduced, thereby protecting the metal.
Simply put, it means that the metal surface is not easily oxidized.