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In the application of passive cathodic protection, a galvanic anode, a piece of a more electrochemically "active" metal (more negative electrode potential), is attached to the vulnerable metal surface where it is exposed to an electrolyte. Galvanic anodes are selected because they have a more "active" voltage than the metal of the target ...
Anodic inhibitors and cathodic inhibitors are the two main categories of corrosion inhibitors. While cathodic inhibitors act as catalysts to slow down corrosion, anodic inhibitors protect metal surfaces by acting as physical barriers. They can also be divided into organic and inorganic corrosion inhibitors based on their chemical composition. [1]
An anodic protection system includes an external power supply connected to auxiliary cathodes and controlled by a feedback signal from one or more reference electrodes. [3] Careful design and control is required when using anodic protection for several reasons, including excessive current when passivation is lost or unstable, leading to ...
A galvanic anode, or sacrificial anode, is the main component of a galvanic cathodic protection system used to protect buried or submerged metal structures from corrosion. They are made from a metal alloy with a more "active" voltage (more negative reduction potential / more positive oxidation potential ) than the metal of the structure.
The difference can be measured as a difference in voltage potential: the less noble metal is the one with a lower (that is, more negative) electrode potential than the nobler one, and will function as the anode (electron or anion attractor) within the electrolyte device functioning as described above (a galvanic cell).
Another example is the cathodic protection of buried or submerged structures as well as hot water storage tanks. In this case, sacrificial anodes work as part of a galvanic couple, promoting corrosion of the anode, while protecting the cathode metal.
Another cathodic protection is used on the impressed current anode. [12] It is made from titanium and covered with mixed metal oxide. Unlike the sacrificial anode rod, the impressed current anode does not sacrifice its structure. This technology uses an external current provided by a DC source to create the cathodic protection. [13]
Depending on whether the reaction on the electrode is a reduction or an oxidation, the working electrode is called cathodic or anodic, respectively. Common working electrodes can consist of materials ranging from noble metals such as gold or platinum , to inert carbon such as glassy carbon , boron -doped diamond [ 4 ] or pyrolytic carbon , and ...