The shiny gray niobium is not unlike tantalum, which also has a very high
melting temperature. A striking difference to tantalum is the significantly
lower density. The pure metal is easy to process due to its low hardness.
However, if it is slightly contaminated with carbon, it becomes much harder and
more brittle. Niobium is a relatively base element. In the air, a protective
oxide layer forms around the metal, which protects it from further corrosion and
provides additional resistance. These wafer-thin oxide layers on the metal
surface cause the colored shimmering that occurs when a compact piece is heated
with the burner. Niobium powder is pyrophoric and can therefore self-ignite.
Glowing niobium powder reacts with oxygen to form niobium (V) oxide.
The compact metal resists most acids at room temperature. After heating,
however, almost all acids are able to decompose the metal. At higher
temperatures it also reacts with most non-metals such as nitrogen or carbon,
hydrogen and also with chlorine.
Niobium - a fantastic and underrated all-rounder
Hardly anyone will get around niobium in their life, even though it is
relatively unknown as a metal. Nevertheless, it combines several properties that
make it a popular all-rounder. The melting point of niobium is very high, almost
2,500 ° C. Despite its exceptional stability and strength, the metal can be
processed very well, which is why it is often used in the construction of
pipelines, high-voltage pylons or high bridge pillars. The successes in space
travel would not have been possible without niobium. The space shuttle had
installed niobium pipes, screws and nuts at its most sensitive points in order
to withstand the extreme temperatures when it entered the earth's atmosphere.
The only catch: There are 41 metals that are more common in the earth's crust
than niobium. Nevertheless, there is no alternative in some areas of
application.
Niobium alloys have almost unlimited possibilities
Materials with niobium alloys are generally characterized by increased
mechanical strength. The slightest addition of niobium makes steel much stronger
and tougher. Anyone who has ever ridden a bicycle has most likely done so on
rims made of a niobium-aluminum alloy, which guarantees lightness and stability.
Even in high-tech areas of application such as particle accelerators as
superconductors at extremely low temperatures or lasers, niobium alloys are
indispensable.
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