Iridium is a kind of platinum element symboled as Ir. As a kind of rare precious metal, it looks silver-white in a crystal structure of face-centered cubic. It got the name from Latin, which means “rainbow" originally and was first discovered by the British chemist Tennant in 1803. Iridium is hard and brittle, so it’s difficult to be processed. It can be extended and processed into filaments and flakes at high temperatures. Its chemical properties are very stable, so it’s insoluble in acids and alkalis. Iridium has very high melting point with strong corrosion resistance and high temperature oxidation resistance. Due to very strong tendency to be compounded and good catalytic performance, it’s a kind of excellent high-temperature coating material. Superconductor is the intermetallic compound of iridium.

Due to the brittleness and complicated processing technology, the application of iridium has been restricted to a certain extent. The alloys compounded with other elements can further improve the thermoelectric performance, high temperature oxidation resistance, corrosion resistance, mechanical and processing performance so that the application field can be correspondingly expanded. The most common iridium alloys include iridium platinum alloy, iridium rhodium alloy and iridium rhenium alloy.

The main properties of iridium

Element name: Iridium (Ir)

Element type: metal

Atomic weight of element: 192.2

Atomic volume :(cubic cm/mole) : 8.54

Melting point: 2410 ± 40 ℃

Boiling point: 4130 ℃

Intensity (kgf/mm2) : 112

Vickers hardness (Y) :240

Density (g/cm^3) : 22.65

Volume modulus of elasticity: Gpa: 320

Enthalpy of atomization: kJ /mol @25℃ : 628

Heat capacity: J/(mol• K) : 25.10

Thermal conductivity: W/（m•K） ：147

Electrical conductivity: 10^6/(cm •Ω  )：0.197

Resistance coefficient ： 6.03×10-2Ωmm2/m

Heat of fusion :(kilojoules/mole) : 26.10

Heat of vaporization :(kilojoule/mole) : 604.0