What causes pitting corrosion?

What Causes Pitting Corrosion? Pitting corrosion occurs when the cathode (damaged coating) is large and the anode (exposed metal) is small. Typically the surface protection layer or film becomes the cathode when it is damaged and cracked. A small area of metal is then exposed and becomes the anodic.

What is the process of pitting?

The more conventional explanation for pitting corrosion is that it is an autocatalytic process. Metal oxidation results in localized acidity that is maintained by the spatial separation of the cathodic and anodic half-reactions, which creates a potential gradient and electromigration of aggressive anions into the pit.

What is pitting metal?

Pitting: corrosion of a metal surface, confined to a point or small area, that takes the form of cavities. * Pitting factor: ratio of the depth of the deepest pit resulting from corrosion divided by the average penetration as calculated from weight loss.

What is the difference between corrosion and pitting?

As nouns the difference between corrosion and pitting is that corrosion is the act of corroding or the condition so produced while pitting is the formation of pits on a surface because of corrosion.

What does pitting mean?

1 : the action or process of forming pits (as in acned skin, a tooth, or a dental restoration) 2 : the formation of a depression or indentation in living tissue that is produced by pressure with a finger or blunt instrument and disappears only slowly following release of the pressure in some forms of edema.

What is galvanic and pitting corrosion?

Galvanic corrosion (dissimilar-metal corrosion) is an electrochemical process in which one metal corrodes preferentially, when in electrical contact with a different type of metal, and both metals are immersed in an electrolyte such as water.

What is cavitation and pitting?

As nouns the difference between cavitation and pitting is that cavitation is the formation of pits on a surface while pitting is the formation of pits on a surface because of corrosion.

What is pitting in food?

The process of removing the seed or pit from an olive or fruit, also referred to as “stone”. The pit is generally removed by cutting it out with a sharp knife or by using a special device, called a pitter, to push it out.

What are galvanic and pitting corrosion?

Galvanic corrosion, also known as bimetallic corrosion, is a common mode of corrosion failure that is, for the most part, entirely preventable by proper corrosion design. Even without galvanic corrosion, metals may suffer from uniform corrosion, crevice corrosion, pitting, or other forms of corrosion.

What are the dangers of corrosion?

The main dangers and effects of corrosion are as follows: High risk of employee injury or injury to the general public Loss of industrial equipment’s time availability When appearance is affected, corrosion can reduce the overall value of a building or location Pipe blockages or mechanical damage to pumps, valves, etc.

What causes concrete pitting?

Pitting in concrete is caused by a wide variety of conditions. Some pitting and spalling , as it is sometimes called, is from natural aging and sometimes it can be caused by abuse or misuse.

What types of metal are suscepitible to corrosion?

Stainless steel Chromium Passive iron Mercury Cobalt Aluminum Copper Associated alloys

What are the different types of corrosion?

There are five general types of corrosion: galvanic, stress cracking, general, localized and caustic agent corrosion. Galvanic corrosion is extraordinarily common, and occurs when two metals with different electrochemical charges are linked via a conductive path.