¿Por qué los sistemas industriales necesitan anticongelante/refrigerante en verano?
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Pasos para la limpieza química de torres de refrigeración: guía de implementación
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Tipos de sedimentos en sistemas de ósmosis inversa y métodos para identificarlos.
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Beneficios de utilizar soluciones especializadas de Abrizan Company para MED
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Selective detachment corrosion
Introduction
In selective delamination corrosion, one of the elements constituting the alloy is selectively corroded, leaving a porous body. This process occurs in certain alloys only under certain conditions and usually occurs very slowly (years).
For example, in the common yellow brass alloy, which is an alloy with a chemical composition of 30% Zn-70% Cu, the separation of zinc in this alloy due to selective delamination corrosion and its change in yellow color to red is called dezincification. As a result of corrosion caused by dezincification, the shape and dimensions of the part usually do not change and it may appear without defects, but its tensile strength and flexibility are greatly reduced.
There are two types of dezincification:
- Uniform or layered type
- Local type
This type of corrosion is also likely to occur in other alloys, for example, some copper alloys such as aluminum bronze lose their aluminum in the presence of acidic environments or seawater due to delamination corrosion.
In bronze objects found in archaeological excavations, the corrosion product layers appear to be enriched in tin.
Alloys of gold or platinum with more active metals, such as silver, nickel, or copper, may be de-alloyed in strong oxidizing acids.
Graphitization
Gray cast iron sometimes exhibits selective detachment, especially in environments that are relatively moderate in terms of corrosion. The surface of the cast iron appears to be graphitized because the surface of the cast iron takes on a graphite appearance and can be easily scraped with a chisel. For this reason, this phenomenon is called graphitization and sometimes graphitic corrosion. This is a misnomer and is actually the selective detachment of carbon from the cast iron alloy.
Methods of controlling or preventing selective delamination corrosion
The most important effective methods in reducing the damage caused by this type of corrosion are:
- Eliminating or modifying environmental corrosive agents such as oxygen.
- Adding some elements to alloys that increase their resistance to this type of corrosion. For example, adding 1% tin to ordinary yellow brass produces a new alloy called Admiralty, which will have considerable resistance. Also, by adding small amounts of arsenic, antimony or phosphorus, delamination corrosion can be slowed down.
- Using the cathodic protection method.
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¿Por qué los sistemas industriales necesitan anticongelante/refrigerante en verano?
1405/03/02Pasos para la limpieza química de torres de refrigeración: guía de implementación
1405/02/07Tipos de sedimentos en sistemas de ósmosis inversa y métodos para identificarlos.
1405/02/05Beneficios de utilizar soluciones especializadas de Abrizan Company para MED
1404/12/09
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