Corrosion, typically defined as the deterioration of metals through the combined actions of oxygen, other metals and salts, has a major impact on industrial economies. But despite the damage it does, and the seriousness of the issue in economic terms, awareness of ways corrosion can be controlled is in surprisingly short supply.
In the United States, Japan, Great Britain and Australia, studies of the economics of corrosion have indicated that its cost to the economy runs in the vicinity of 3-4 per cent of Gross National Product.
Further, in a world where businesses are looking for ways to simultaneously stretch budgets and address concerns about the sustainability of their processes, corrosion presents another problem. Of the new steel consumed every year around the world, it is estimated that roughly 20 per cent is used to replace metal lost to corrosion.
As is often the case, the reality on the ground is a lot messier than the scientific explanation. In theory, corrosion processes are easy to describe, but the truth of the matter is that corrosion is a multi-phased process that can sometimes result in secondary chemical agents that are as damaging as the corrosion itself. Hydrogen evolution is a good example of this. While corrosion is the main culprit, the resultant processes further weaken metallic components.
Likewise, the corrosion resistance properties of various metals – often thought of as a cut-and-dry matter – are much more complex than they appear at first glance.
Considering the cost it exacts on our economy, it is surprising that corrosion is such a misunderstood process, and that it is often treated as an uncontrollable cost of doing business. By acquiring knowledge of the corrosion process, we can better understand how to limit its negative effects.
This paper provides a brief overview of corrosion and explores how best to control it by examining its impact on the three most commonly used metals in electrical installations: copper, steel and aluminum.