• General 20.11.2012 Comments Off on Oxygen Corrosion

    This is a phenomenon that develops in metals especially iron and steel as these have to go back au natural state, which is in the form of oxide, so it can be said that the effort to avoid it is virtually against "nature", according to this fact so the only thing you can do is minimize the effects of it. Usually we hear the expression "has been or is rusting" in reality is not entirely accurate, but it reflects the above, the steel is forming oxides, the phenomenon is of such magnitude that organizations approach it as one of its main tasks maintenance and represents a very important item in the cost of this activity. The phenomenon itself has some origins from which we can specify the following: Oxygen Corrosion .- It is given with the aid of heat and pressure, is common in the generation and transmission systems and specifically steam in the condensate return lines by effects of free oxygen is in the air and water. Corrosion .- biological usually occurs in the submerged, as this condition favors the growth of life, and acts to the extent that some species produce sulfuric acid, which erodes the metal surface. Hot Corrosion .- Associated with the presence of vanadium and sodium is formed at temperatures above 700 C and causes a very strong erosion on the surface in contact with these elements, it is common in engines that run on Bunker or raw. Corrosion in Cold .- Produced primarily by Dissolved sulfur in fossil fuels, that with the presence of water vapor, sulfuric acid reacts causing sulfide, which erode metal surfaces, it is common practice to identify exhaust pipes destroyed by this type corrosion. .- Galvanic corrosion is given by the migration of electrons from an element called the anode, which is oxidized to another called cathode is reduced, so that this phenomenon is always necessary verified the presence of three components, the anode cathode and electrolyte or means of transmission, this is the way, more common, is corrosion and corrosion variants partial pressures and salt corrosion activity differently. It is clear that the rates mentioned here in any way show all types of corrosion, however, reflect the most common. The means of preventing or avoiding it are numerous and may involve actions ranging from the very design of the metal, its geometry, material type surface hardness, etc to the application of shielding the same, it is interesting to note that the most used, is, the same oxide layer that forms immediately to the bare surfaces, confining the moisture to the outside of it, as is the case of sodium oxide coating that forms in the material immediately after cutting, or opaque roof that appears on copper after machining, it is clad stainless steel with chromium and nickel oxides, which are very sticky that give protection However when oxide coating is not enough (usually because it is easily detached), gets used other protection, applying a protective film as anti-corrosive paint, or using other electro deposited metal (electroplating).

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