![]() ![]() As it is well known the electrochemical corrosion is the result of local galvanic cells forming on the metal surface. This is an active device and requires power, however, it generates a much higher voltage which affects its efficiency and miniaturization. Thus, passive method is used which is based on the natural potential differences of metals. In these cases other methods of corrosion maintanance would be virtually impossible on those huge surfaces. The method has been used for years to protect ships and in the building industry to protect reinforced concrete structures, underground tanks and pipelines from corrosion. ![]() Method of the operation of our device is well known and used in the industry as cathodic corrosion protection. Thus, in the case of anodic coating of metal surfaces, the coating doesn’t have to be perfectly sealed. In this situation, zinc ions go into solution instead of iron ions. When cracks or fissures appear, a cell is formed in which the cathode is iron and the anode is zinc. The most important practical application of anodic coating is galvanizing – the application of a zinc coating on steel surfaces. Examples of anode coatings are zinc and cadmium. Anodic coatings of metals provide the protected metal with cathodic protection as the coating made of less precious metal is made the anode and acts as a protector. Anodic coatings (protectors) are made of metal with a more negative electrode potential (less noble) than the metal being protected. After being used, the protectors are exchanged for new ones. In the cell formed this way, the anode is the protector which corrodes. Protectors are made of sheet metal or bars of active metals such as zinc, magnesium or aluminium, with the wires connected to a protected object. With the use of protectors large steel objects such as ship hulls, pipelines and underground tanks are protected against corrosion. It is accomplished by direct contact (so-called anodic coating) or with a conductor. ![]() The simplest method to apply CP is by connecting the metal to be protected with a piece of another more easily corroded "sacrificial metal" to act as the anode of the electrochemical cell. Cathodic protection is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. Corrosion of metals usually manifests itself in metal surface defects (stains and pitting), or the reduction of the metal strength.Ĭathodic protection is an electrochemical corrosion protection. at the interface between various metals, or as a result of heterogeneity in the crystalline structure of the metal. These cells are formed as a result of chemical heterogeneity (or physical) of a metal, e.g. It is one of the common atmospheric corrosion phenomena,which is caused by the action of moist impure air on metals.Electrochemical corrosion occurs when short-circuited cell stake action on the interface between a metal and an electrolyte. Electrochemical corrosion is the most common type of corrosion. The corrosion process caused by mentioned corrosion cells is the anodic process – the formation of positive ions from the metal atoms. In the case of atmospheric corrosion the electrolyte is condensed moisture and rain water always containing a certain amount of dissolved substances such as oxygen, carbon dioxide, sulphur dioxide, nitrogen oxides, and others. In any case, an important component of those cells is the electrolyte solution. The most common and well-known corrosion is galvanic corrosion, which is the result of local galvanic cells formed on the surface of the metal. To understand the nature of our device we need to know what it is to prevent. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |