Marine_Corrosion.pdf - General Corrosion Corrosion is the destructive attack of a material by reaction with its environment Rust is the most well-known

Marine_Corrosion.pdf - General Corrosion Corrosion is the...

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1 General Corrosion C orrosion is the destructive attack of a material by reaction with its environment Rust is the most well-known corrosion product, which is yielded when steel and iron involve in the corrosion process. Figure 1 gives a basic schematic of a corrosion cell. As corrosion damage costs a lot of money to repair, methods which are able to prevent corrosion are given great importance. It is stated that between 3 and 5 percent of the gross national product (GNP) of industrialised countries is associated with corrosion damage. Corrosion of metals causes the U.S. economy to loose approximately $300 billion each year. Incredibly, 33 % of this cost could be prevented by the selection and use of an appropriate corrosion protection system.
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2 Ships are coated to prevent corrosion. This protective layer, however, is not sufficient to fully protect the ship from corrosion. For this reason, as well as to protect the uncoated sections of a ship (screw, damage, etc.) and ensure that the ship remains protected as the coating deteriorates, cathodic protection is used. If two metals are electrically connected in an electrolyte (such as seawater), the electrons of a base metal will flow to another, more noble metal. This is due to the difference in electrical potential. The more noble metal is referred to as the "cathode" and the other as the "anode." As the anode supplies electrons to the cathode, it gradually dissolves into ions, with the result that the cathode becomes negatively polarized and thus protected against corrosion. Cathodic protection can be classified as passive or active. Introduction to Marine Corrosion
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4 How to control Marine Corrosion Effective corrosion control of ship structure is one of the most important challenges in the shipping industry to ensure reliability and minimize risk. The problem of corrosion of the ship hull has become a major concern for owners, as they have recognized the need for more and more to protect your investment and to demonstrate a commitment to maintain the structural integrity of the ship. Corrosion can be minimized by mainly two methods . One method is the technical approach, which involves coating, cathode protection and inhibitors, etc. The other method is a method of management (CM), which is less technical and more manageria l, and was not a major concern for owners for many years. To ensure the continued integrity with minimal costs, erosion must actively manage the planning phase until the end of life ships. Erosion Management System is an approach that includes all aspects of the human factor in reducing the risk of corrosion failure. Management of erosion associated with the development, implementation, revision and maintenance of corrosions policy. Policy of corrosion provides a structural framework for identifying risk for corrosion and the development and operation of appropriate measures to control the risks. Policy is to minimize the risk of corrosion failure and major renovation of the hull structure and prolong the life of the vessel by the proper management of corrosion.
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  • Summer '17
  • Duncan kiplimo
  • Marine Corrosion

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