This is not another boring science topic that will put you off to sleep. Trust me, I'll make this as simple and as interesting read as possible.

Corrosions dictionary meaning is synonymous to a list of words like rusting, corroding, erosion, a chemical process, a chemical change, a chemical action a natural activity, deterioration of metals through the process of oxidation or chemical action.

Whew!

To explain it further, corrosion is defined as the wearing away of materials in a slow blow by blow process. It does not literally pertain to the destruction of metals and other related materials.

Corrosion is then followed by reversion to a more subtle and balanced pairs or combination where metals are known as the most popular examples. Corrosion, in short, is the opposite of metallurgy.

Because while metallurgy is the molding and making of metals, corrosion on the other hand, is the rusting, corroding and unmaking of metals caused by a chemical reaction between the metal and its external faculties which makes up its environment.

Corrosion, in its broadest studies are subdivided into a number of categories with each type processing a different characteristic from the other.

But for a more comprehensive study and understanding of corrosion, scientist have specifically classified corrosion into 2 general and most known types and methods in which the process of unmaking the metals can take place.

The first of which is typified corrosion whereby metal iron is exposed to its external agencies during which the temperature is high or eleveated. During typified corrosion, the corroding and rusting of the metal begins as soon as the oxygen in the atmosphere to produce mill scale, a common product formed whenever oxygen reacts with its surroundings.

Mill scale and magnetite, which plays a vital role in the method of typified corrosion, contains the same chemical composition called iron ores.

Other forms of metals behave in the same way when associated to its external environment, they also produce varieties of oxides and may have the tendency to behave in the similar manner to come up with other compounds.

All of these chemical reaction and activity points to summarize that the result of direct combination between the given reacting elements results to products of corrosion, and does not plainly embody the end product formed through the substitution of or displacement of an element for or by another element.

However, the second type and method of corrosion is referred to as galvanic corrosion or electrochemical corrosion.

This method is characterized by the process of displacement of one given element in one phase (usually in the form of alloy or metal). And since electric current is the focal point of the variable displacement of one given element by the other given element, literally defining the very meaning of galvanic or electrochemical corrosion.

Furthermore, electrochemical corrosion generally refers to cases of corrosion in which metal or alloy being rusted is continuously associated and linked with the corrosion-causing solution, or another given element that is a dissimilar metal or may also be some different conducting or solid material.

The term electrochemical corrosion may also be used in cases when either pure metal, impure metals, or other forms of metal or alloys are exposed to pure water, aqueous solution of water soluble materials, or different mixtures of water with other elements which is both not soluble nor a solvent of water.

Corrosion will not take place in the absence of corrosion cells. In a more simplified situation, its like a cheeseburger without cheese. Before such corrosion cells do their function, some pre-requisites must be met.

First requirement is for cells to have doors to connect two points, the metal and the solution, to allow the flow of electric current to and from each other in the metal surface.

Second, the cell must be capable of electric conductivity. And lastly, there must be a motivating force or push that will enable the initiation (first step), and maintenance (second step) of flow of current all throughout the system.