Definition of anode - What it is, Meaning and Concept

The notion of anode is used in the field of physics to name a positively charged electrode .An electrode, by its part, is the end of a conductive material that, being linked to a medium, transfers or obtains from it an electric current (a flow of charges).

The etymology of the anode leads us to an expression Greek that can be translated as "ascending path" .The British scientist Michael Faraday (1791-1867) was the one who used the concept for the first time.

In the anode a reaction of oxidation is generated: it increases its oxidation state from the loss of electrons.It should be remembered that, in this type of reactions, the reducing agent yields electrons to the medium and increases its oxidation state (oxidizes), while the oxidizing agent receives these electrons and minimizes its oxidation state (reduces).

The anode, when oxidized, allows the passage of electric current to the negative pole, called cathode .In the batteries (also called batteries ), the electrical sources and the electronic valves , the anode is characterized by being the electrode that has the greatest potential.

Take the case of a voltaic cell .This element generates electrical energy through the oxidation-reduction reactions that occur inside, where two metals are connected by a saline bridge or there are related semi-cells through a membrane with pores.The anode in these cells can be zinc or other material.

It is called galvanic anode or of sacrifice , finally, the piece used to provide protection against corrosion in a metal structure that is submerged or buried.In the field of nautical, for example, it is very important to ensure that electrolytic corrosion does not damage any of the parts that are inevitably submerged from a ship, such as the shovel of its helm, helix, shaft, drift or keel.

It is called electrolytic corrosion or electrolysis to a deterioration that the emergence of an electric current causes in the submerged metals, which are grouped according to their potential: the cathodes are the which have greater potential, while on the other side are the anodes, which decompose instead of the first.

It is important to note that the action of the anode is subject to the nature of the water.Based on this factor, there are different types of anodes, such as the following:

* sacrificial anode of zinc : it is used in salt water, as well as that of aluminum, since in this medium the resistivity is usually lower.The most common applications of this type of anode are the production platforms, the rudders and the propellers of small vessels, the interior surface of storage tanks, boat hulls and marine engines that are cooled with salt salt;

* magnesium sacrificial anode : Magnesium is a metal with a particularly low, negative electrical potential, and is therefore ideal for areas where the electrolyte resistivity is higher.anode is used in fresh water, both on ships and in water heaters.Despite being a frequent option, magnesium can cause problems if the protected metal has a potential too negative, since that the mobilization of hydrogen ions in the cathode can lead to the coating coming off;

* aluminum slaughter anode : aluminum , which is used in brackish water, offers a good number of advantages over the aforementioned metals, such as a lower weight and a greater capacity.On the other hand, since its electrochemical behavior is not as stable as that of zinc, for example, it should not be used without taking certain precautions.