Refractory metals are different. As a group they provide a number of unique characteristics – such as resistance to high heat, corrosion and wear – making them useful in a multitude of applications.
The next time you climb into your automobile take note that you are surrounded by components which are made of refractory metals or have been cut or formed by them. Your car’s electrical or electronic systems may also make use of the metals’ electric and heat-conducting qualities. On the other hand, refractory metals were used in the tools which helped to drill the well which produces the gasoline in your tank. Piping of refractory metal alloys helped process it. And your oil may contain a refractory metal compound to increase its lubricating ability.
The paradox of refractory metals is that, despite their wide and constantly growing list of applications, many people – sometimes even engineers, working with one of the metals – do not fully understand how and where each is mined, how it is processed, how it is formed, or even understand the full extent of the diversity of refractory metals’ applications.
Refractory metals have one characteristic in common: an exceptionally high melting point. Tungsten, for example, melts at 3410oC (6170oF), which is more than double that of iron and ten times that of lead.
As a group, they are found in one section of the periodic table of elements. Although there are twelve refractory metals, only five are widely used: Tungsten, Molybdenum, Niobium, Tantalum and Rhenium.
All but Rhenium have a body-centered cubic structure. Despite the fact that refractory metals have many similar qualities-such as high density, resistance to wear and corrosion-each metal is different in its own way, providing each with its own individual combination of qualities. Many of these individual qualities are rather unique, such as an ability to combine with gases and then release them under heat. Or, remarkable lubricating qualities.
This selection of unusual characteristics provides engineers with a virtually uncountable number of potential applications … each a key to solving a problem.
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