Iridium

Iridium may be fabricated using conventional powder metallurgy techniques, although it is primarily used as an alloying element. Pure iridium is used in high performance spark plugs and very high temperature crucibles for single crystal preparation. It is used as a hardener and for increased corrosion resistance when added to palladium and platinum. Iridium containing 30% platinum have been used in chemical handling equipment for extremely corrosive materials and for electrical contacts in severe environments. Iridium is the most corrosion resistant metal known. It is highly resistant to virtually all acids at room temperature and at 100ºC. Iridium is slightly attacked by fused sodium, potassium hydroxides, fused sodium bicarbonate, and aqueous potassium cyanide. It has the highest resistance of the noble metals to halogen compounds, with a measured susceptibility only to moist bromine. Iridium can be dissolved in a hot aqua regia solution.