What metals corrode the fastest?

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ALREADY IN CHAPTER II we mentioned that some metals are more active than others due to the accumulated energy they possess. In this chapter, we will focus on the nature of these energies, their quantification and the effects they have during a corrosion process.

The energies of an atom thus arise from correlation energies due mainly to interactions between electrons affecting their electrostatic field. This is very important in elemental chemistry since the energies involved are directly related to chemical reactivities or to the different tendencies to change from a free state, as in the case of a metal, to a metal ion state, where the atom has given up one or more electrons.

To illustrate this difference, let us take from nature the example of the so-called noble metals such as gold and platinum, which are usually found as free metals in the earth and not as compounds. On the other hand, there are the so-called active or base metals such as sodium, aluminum and magnesium, which can never be found as free metals in our earth’s atmosphere, but as compounds. There are occasions in which certain metals with intermediate activities to those mentioned above, can be found in the earth as free elements. Examples of such metals are copper, silver and iron.

Corrosion of metals

Corrosion is defined as the deterioration of a material as a result of electrochemical attack by its environment. More generally, it can be understood as the general tendency of materials to seek their most stable or lowest internal energy form. Whenever corrosion is caused by an electrochemical reaction (oxidation), the rate at which it takes place will depend to some extent on the temperature, the salinity of the fluid in contact with the metal and the properties of the metals in question. Other non-metallic materials also undergo corrosion by other mechanisms. The corrosion process is natural and spontaneous.

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The best known factors are the chemical alterations of metals due to air, such as rust on iron and steel or the formation of green patina on copper and its alloys (bronze, brass).

It is a major industrial problem, as it can cause accidents (breakage of a part) and also represents a significant cost, since it is estimated that every few seconds five tons of steel are dissolved in the world, coming from a few nanometers or picometers, invisible in each piece but which, multiplied by the amount of steel in the world, constitute a significant amount.

Why metals oxidize

ALREADY IN CHAPTER II we mentioned that some metals are more active than others due to the accumulated energy they possess. In the present chapter we will emphasize the nature of these energies, their quantification and the effects they have during a corrosion process.

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The energies of an atom thus arise from correlation energies due mainly to interactions between electrons affecting their electrostatic field. This is very important in elemental chemistry since the energies involved are directly related to chemical reactivities or to the different tendencies to change from a free state, as in the case of a metal, to a metal ion state, where the atom has given up one or more electrons.

To illustrate this difference, let us take from nature the example of the so-called noble metals such as gold and platinum, which are usually found as free metals in the earth and not as compounds. On the other hand, there are the so-called active or base metals such as sodium, aluminum and magnesium, which can never be found as free metals in our earth’s atmosphere, but as compounds. There are occasions in which certain metals with intermediate activities to those mentioned above, can be found in the earth as free elements. Examples of such metals are copper, silver and iron.

What is the name for metals that do not rust?

In this article we will discuss the metals found in swimming pools and how they relate to other substances in the water, such as chlorine, and how to prevent some problems such as rust stains. We will cover oxidation, sequestering and chelation and try to keep it simple and easy to understand.

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Water is the universal solvent and can eventually dissolve almost anything.  Yes, this includes metallic minerals such as calcium and magnesium, and also includes heavy metals such as copper, iron, manganese and silver.  Unlike minerals (calcium and magnesium), heavy metals are oxidizers, meaning they oxidize in the presence of chlorine.  Calcium and magnesium do not.

Because heavy metals such as copper and iron oxidize, they are also known as reducing agents, because their electrons will reduce chlorine. So when we say that chlorine has been depleted at the beginning of the breakpoint during the chlorination process, it is because the metals have reduced it. More chlorine is needed to overcome the metals in the water and continue the chlorination process after the breakpoint. We can identify the process in the table below.