Metal is one, if not the, most common and most useful substance on the planet. Its application is as boundless as its reliability as a material. But, this does not mean that metal is exempt from the wear of nature and time.
Corrosion is a serious, at times life-threatening consequence of people’s overconfident overreliance on metal. Maintenance is key, and it is the only way to prevent metal from failing as a building material.
The following is a primer on the science behind metal corrosion:
- Corrosion is any instance of metallic disintegration through an unintentional chemical or electrochemical action.
- It always begins at the surface.
- All metals are susceptible to oxidation, but some more than others. Industries relying on metal refer to the galvanic series to find the type of metal best suited for their intended application. It is a tabulation of all metals arranged according to the relative strength of their tendency to corrode.
- Corrosion is not always a bad thing. In fact, corrosion is the only way by which the mining industry produce certain useful ores, such as hematite, an oxide of iron.
- Observed colour changes in corroded metal are results of the freed thermodynamic or chemical energy stored in a metal.
- Of course, the stored energy varies between metals. For example, metals such as magnesium, aluminium and iron release more energy and change more in appearance compared to metals such as copper, silver and gold.
- Corrosion control specialists agree that the process does not have to be prevented at every turn – only where it counts. Since it is very difficult to keep metals pure, or at their zero oxidation state, they say that the best people can do is focus their efforts on areas where corrosion prevention is imperative.
With sufficient understanding of corrosion, how and why it begins, individuals who need to keep their metallic equipment or structures from breaking down can channel their efforts in a way that is effective and practical.