Notable characteristics:
Iron is a
chemical element with the symbol Fe (L.:
Ferrum) and
atomic number 26. Iron is a
group 8 and
period 4
metal. Iron is notable for being the final element
produced by
stellar nucleosynthesis, and thus the heaviest
element which does not require a
supernova or similarly cataclysmic event for its
formation. It is therefore the most abundant heavy metal
in the universe.
Iron is the
most abundant metal on
Earth,
and is believed to be the tenth most abundant
element in the
universe. Iron is also the most abundant (by mass, 34.6%) element
making up the Earth; the concentration of iron in the various layers of
the Earth ranges from high at the inner core to about 5% in the outer
crust; it is possible the Earth's inner core consists of a single iron
crystal
although it is more likely to be a mixture of iron and
nickel;
the large amount of iron in the Earth is thought to contribute to its
magnetic field.
Iron is a
metal extracted from iron ore, and is hardly ever found in the free
(elemental) state. In order to obtain elemental iron, the impurities
must be removed by chemical
reduction. Iron is used in the production of
steel,
which is not an element but an
alloy, a
solution of different metals (and some non-metals, particularly
carbon).
Nuclei of iron have some of the highest binding energies per nucleon,
superseded only by the
nickel isotope
62Ni. The universally most abundant of the highly stable
nucleides is, however, 56Fe. This is formed by nuclear fusion
in the stars. Although a further tiny energy gain could be extracted by
synthesizing 62Ni, conditions in stars are not right for this
process to be favoured. When a very large star contracts at the end of
its life, internal pressure and temperature rise, allowing the star to
produce progressively heavier elements, despite these being less stable
than the elements around mass number 60 (the "iron group"). This leads
to a
supernova.
Some cosmological models with an open universe predict that there
will be a phase where as a result of slow fusion and fission reactions,
everything will become iron
Applications:
Iron is the most used
of all the metals, comprising 95 percent of all the metal tonnage
produced worldwide. Its combination of low cost and high strength make
it indispensable, especially in applications like
automobiles, the
hulls of large
ships, and
structural components for
buildings.
Steel is
the best known alloy of iron, and some of the forms that iron takes
include:
Carbon steel contains between 0.4% and 1.5%
carbon,
with small amounts of
manganese,
sulfur,
phosphorus, and
silicon.
Alloy steels contain varying amounts of carbon as well as other
metals, such as
chromium,
vanadium,
molybdenum,
nickel,
tungsten, etc. They are used for structural purposes, as their alloy
content raises their cost and necessitates justification |