Galvanic corrosion (also called ' dissimilar metal corrosion' or wrongly 'electrolysis') refers to corrosion damage induced when two dissimilar materials are coupled in a corrosive electrolyte. Galvanic Corrosion can be prevented by the following ways: 1)  Jointing of dissimilar metals can be avoided. All Different Forms of Corrosion are explained by NACE certified Corrosion Specialist (#5047). (Read Corrosion Fatigue of Welded Joints on Marine Offshore Structuresfor more information.) Galvanic corrosion or "Bimetallic Corrosion" or "Dissimilar Metal Corrosion", as sometimes called, is defined as the accelerated corrosion of a metal because of an electrical contact (including physical contact) with a more noble metal or nonmetallic conductor (the cathode) in a corrosive electrolyte. For this joint, Aluminium acts as Anode and Copper as Cathode as decided from for electrode potential of copper (+0.34 Volt) and Aluminium (-1.66 Volt). – Construction and Working Principle, Binary Coded Decimal or BCD Number Explained, What is UPS? Necessary Condition for Galvanic Corrosion: Two different metals are in electrical contact. But it is not practical to avoid such joints. The ability of the metal electrode to lose electrons and to become oxidized is known as oxidation potential. WebCorr provides corrosion consultancy services, corrosion expert witness and corrosion short courses for in-house training, online and distance learning. Galvanic corrosion also is also known as bimetallic corrosion or dissimilar corrosion. This potential difference causes the flow of electrons within the cell. Galvanic corrosion is a leading cause of worry among those who have metal roofing systems. This reduces the current density at anode and hence the corrosion. This is a good example of galvanic corrosion. A typical bimetallic is shown below. Thus anode surface are should be increased over cathode surface area. Understanding how and why galvanic corrosion occurs can help those in the field provide better service to their customers. Cause and Prevention of Galvanic Corrosion in Aluminum Cause Four conditions must be present for galvanic corrosion to occur: • Cathode - the more noble or least active metal. 1)    Two different metals are in electrical contact. 1.How larger anode and smaller cathode can prevent galvanic corrosion? In industries we often need to make electrical joint of two different metals. Sorry!, This page is not available for now to bookmark. The potential difference between the two metals is, therefore, the difference between their respective electrode potentials as defined in the galvanic serie… Let us take an example of Copper to Aluminium joint. A similar galvanic reaction is exploited in primary cells to generate a useful electrical voltage to power portable devices. From the net equation, it is clear that the product of reaction is Al+3 and solid copper. From the net equation, it is clear that the product of reaction is Al. Some important heavy metals are copper, mercury, tin, nickel, and lead. Galvanic corrosion (also called bimetallic corrosion) is an electrochemical process in which one metal corrodes preferentially when it is in electrical contact with another, in the presence of an electrolyte. And use of chemicals to kill bacteria and other microbial life to keep water pure is also a source of galvanic corrosion. It occurs when two (or more) dissimilar metals are brought into electrical contact under water. It is not only costly to Continue Reading The entire mechanism depends upon the oxidation potentials of the two metals in the galvanic corrosion. 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