Iridium is a transition element of Group VIII in the Periodic Table. Iridium tube is main product of iridium, and it is also an important part of tungsten stream mouth. Tungsten stream mouth is composed of iridium tube and tungsten body. Therefore, it is of important reference value to study the properties of iridium for producing tungsten stream mouth.

Iridium is an element of platinum group, which has the same features with other elements in platinum group, but, it also has its own characteristics.

Main Properties of Iridium
1. With the most outstanding anti-corrosion property;
2. Usually hot processing;
3. To form a natural alloy;
4. High erosion resistance to silicate at high temperature;
5. Good erosion resistance to many kinds of molten reagents;
6. A strong tendency to form coordination compound;
7. Iridium in dense state is not soluble in all inorganic acids, not be etched by other metal melts, such as molten nickel, gold, iron, lead and zinc;
8. At room temperature, dense iridium has excellent corrosion resistance to dry fluorine gas, as well as dry or wet chlorine, bromine and iodine. There is no visible corrosion;
9. With good plasticity above 1600°C;
10. Chemical stability, insoluble in ordinary acid, and not soluble in aqua regia;
11. Smelted in intermediate frequency furnace (IF furnace), high frequency furnace, electric arc furnace and electron beam;
12. Highly dispersed in a variety of ores;
13. A rare precious metal material with high elasticity modulus, low Poisson's ratio and poor low temperature plasticity;
14. Mainly exist in the osmiridium mine;
15. Iridium alloy firmly adsorb organics to be used as catalyst material;
16. Not be corroded by common corrosive agents.