This method is also effective in the corrosion of metals, where there is no polarization of the anode sites. Cathodic protection Cathodic protection based on application of cathodic current is called the cathode. It is implemented in a production environment in two ways. The first required a shift in potential provided by connecting the product to be protected as a cathode to an external power source. As an auxiliary anode used inert electrodes. So to protect oil platforms, welded metal foundation, underground piping. Cathodic protection is effectively used to suppress not only the general corrosion, but also the different types, such as to prevent pitting (a type of corrosion, which centers in early stage have the form of points, but in the developed state – corrosion pits) stainless steel and aluminum, stress corrosion cracking of brasses magnesium, intergranular corrosion of stainless steel. Other version of this form of protection – sacrificial or galvanic cathodic protection.
In this case, the cathodic polarization of metal is achieved by contact with his more electronegative metal. The latter, in conjunction with protected the metal acts as the anode. Its electrochemical dissolution of the cathode provides the flow of current through the protected metal. Learn more at this site: Angela Mancini. The very same anode (usually magnesium, zinc, aluminum and their alloys) are gradually fully destroyed. This type of protection is used for relatively small structures or additionally coated with insulation metalloobektov (eg pipelines) with low power consumption.
Said protection is effective. With a magnesium anode protects up to 8 km of pipeline with a coating without him – just 30 meters Protector is widespread, for example in the U.S. for the production of anodes annually consumes about 11.5 million kg of aluminum.