What Is Iridium?
Iridium is one of the rarest elements in the Earth’s crust. It is a transitional metal belonging to the Platinum Group Metals (PGMs). It closely resembles platinum
in appearance - silvery-white but with a slight yellow tinge. Iridium is usually found combined in an alloyed state with other noble metals in gravel deposits. It most often alloyed with osmium
and, like osmium, it is extremely dense. Iridium is the most corrosion resistant metal.
Iridium is very hard, brittle and has a high melting and boiling point, making it difficult to form and work. At temperatures below 0.14 K iridium becomes a superconductor.
What Is Iridium Used For?
Despite the difficulty in machining and working iridium, and its high cost, iridium is used where mechanical strength is needed. It is often alloyed with platinum. One very special use of the iridium-platinum alloy is its role in the weights and measures standard for the kilogram.
When alloyed with titanium
it used for deep water pipes. When combined with osmium it is used in creating gold tip pens and crucibles used in computer memory devices. Iridium has also been used in spark plugs, pivot bearings and compass bearings. Iridium has been used in the making of surgical pins and hypodermic syringes and has been used in cancer irradiation (gamma radiation).
Where Is Iridium Produced?
Iridium reserves are found in South Africa, Canada, Russia, North America and Colombia. It is mostly produced by Canada, Russia and South Africa as a by-product of nickel
Iridium is found in its pure native form in osmiridium. It has is a lustrous, silvery-white metal with a slight yellowish tint and is a member of the PGMs. It is the most corrosion-resistant metal as it is unaffected by water, air or acids, although it does react with molten salts and bases.
Iridium is used as a strengthening agent and is alloyed with other metals, especially platinum which are then used in electrical contacts and spark plugs. Iridium has also been used in medical practices and equipment. Canada, Russia and South Africa are the largest producers of iridium.
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Image courtesy of Wikipedia.