Definition - What does Iridium mean?
Iridium is a rare chemical element and is the most corrosion-resistant element known. Once, gold and platinum were considered to be the exemplars of the pure metals, however, studies have proven that iridium is much better in resisting corrosion than any other metal. It is very hard, brittle and has a silvery white appearance. Historically, iridium was mixed with alloys and was used to manufacture the nibs of premium fountain pens, however, with time, more efficient techniques have been developed and iridium was replaced with a cheaper material such as tungsten.
Corrosionpedia explains Iridium
These days iridium is primarily used to manufacture the central electrodes of spark plugs as it can withstand temperatures as high as 3632 °F (2000 °C) and remain very hard and corrosion-free. Apart from spark plugs, this chemical element is also used in other devices that operate at very high temperatures.
Boiling Point 8180 °F (4527 °C)