Corrosion process Explained, please contact us if you continue to have any questions.
Frequently Asked Questions: The Corrosion Process Explained
Corrosion is deterioration of useful properties in a material due to reactions with its environment. Weakening of steel due to oxidation of the iron atoms is a well-known example of electrochemical corrosion. This type of damage usually affects metallic materials, and typically produces oxide(s) and/or salt(s) of the original metal. Corrosion also can refer to discolouration and weakening of polymers by the sun's ultraviolet light.
Electrochemical corrosion causes between $8 billion and $128 billion in economic damage per year in the United States alone, degrading structures, machines, and containers. Most structural alloys corrode merely from exposure to moisture in the air, but the process can be strongly affected by exposure to acids, bases, salts and organic chemicals. It can be concentrated locally to form a pit or crack, or it can extend across a wide area to produce general deterioration; efforts to reduce corrosion sometimes merely redirect the damage into less visible, less predictable forms
The Corrosion Process
The following will treat corrosion as a process which cannot occur without the presence of water and therefore excludes other types of attack, such as those associated with high temperature oxidation or sulphidation.
Corrosion is a naturally occurring electrochemical process. The presence of a tiny amount of electrolyte on an unprotected metal surface can cause electrons to flow from a higher energy area (anode) to a lower energy area (cathode) initiating and sustaining corrosion. Microscopic droplets of water that are present in the air at 70-85% relative humidity most commonly serve as the electrolyte.
One way to understand the structure of metals on the basis of particles is to imagine an array of positively-charged ions sitting in a negatively-charged "gas" of free electrons. Coulombic attraction holds these oppositely-charged particles together, but there are other sorts of negative charge which are also attracted to the metal ions, such as the negative ions (anions) in an electrolyte. For a given ion at the surface of a metal, there is a certain amount of energy to be gained or lost by dissolving into the electrolyte or becoming a part of the metal, which reflects an atom-scale tug-of-war between the electron gas and dissolved anions. The quantity of energy then strongly depends on a host of variables, including the types of ions in solution and their concentrations, and the number electrons present at the metal's surface. In turn, corrosion processes cause electrochemical changes, meaning that they strongly affect all of these variables. The overall interaction between electrons and ions tends to produce a state of local thermodynamic equilibrium that can often be described using basic chemistry and a knowledge of initial conditions. - en.wikipedia.org/wiki/Corrosion
The presence of Rustblock® on the surface of the metal inhibits the flow of electrons from anode to cathode thus preventing the corrosion process. Rustblock® is an effective Corrosion Inhibitor, which is also safe on metals. Rustblock® automatically releases protective particles into the area around the exposed metal surface. These particles attach themselves to the metal surface and create a protective layer, thus preventing the catastrophic effects of corrosion.
More Corrosion Definitions on the WEB
Chemical or electrochemical attack on the surface of a metal eg rusting. Corrosion is particularly a problem for marine farms, where annual painting of non galvanised steel or iron equipment is essential, to prevent equipment failure. Sacrificial anodes are often used on pumps and other devices to limit corrosion.
The gradual deterioration of material by chemical processes, such as oxidation or attack by acids; if caused by an atmospheric effect, a form of weathering. Of great significance is the corrosion due to the combined effects of atmospheric temperature, humidity, and suspended impurities, for example, the rusting of iron, the direct effects upon a surface wetted by acid water. Compare corrosion, erosion. Brooks, CEP, 1951: Climate in Everyday Life.
Corrosion occurs in all metals at some time and can be divided into four basic forms. Room temperature oxidation, the most common form, is most obvious in mild and low-alloy steels. The process is accelerated dramatically by comparatively small amounts of contaminants like chloride, sulfate, and fluoride. When exposed to high temperatures, metals will almost invariable result in oxidation of metal surfaces. Chemical corrosion is the result of attack by acids or alkaline compounds which dissolve the metal surface. Electrolytic corrosion occurs when two metals in contact with each other have different electrode potentials. It is a major contributor
Corrosion is the deterioration of a materials useful properties due to reactions with its environment. e.g. Weakening of steel due to oxidation of the iron atoms. Corrosion also includes the discolouration and weakening of non-metals by the sun's ultraviolet light.