- One of the platinum-group metals.
- Like platinum, it is a white metal, though with a glint of yellow.
- Very hard and brittle.
- Its volumic mass (22,420 kg/m3) is only slightly less than that of osmium (22,570 kg/m3).
- Iridium has catalytic properties which enable its use in hydrogenation
- In the automotive industry, iridium is used mainly as a component of exhausts for direct injection (GDI) engines and, to a lesser extent, in spark plugs. In the form of alloys with ruthenium, the metal is used in the manufacture of electrodes for the production of chlorine by electrolysis.
- Iridium has also been used since 1995 as a catalyst in the production of acetic acid.
- Iridium linings and fabrications are also used in glass production because the metal is inert in contact with molten glass
- Other applications include crucibles used to grow synthetic single crystals for LED and data-storage technologies.
- Iridium also serves as an alloying element to harden the platinum used in pacemakers, medical probes and other applications of this type.
- The 90% Pt–10 Ir alloy has an extremely low thermal expansion coefficient. It was selected to make the standard metre kept at the “Pavillon de Sèvres” in France.
Recycling accounts for a small proportion of the metal produced globally each year.
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