Iridium alloy can use a small amount of tungsten or hafnium improve the processing properties of iridium, mixed with trace aluminium, iron, thorium, such as improving the impact toughness, so of iridium alloy with high melting point and high temperature strength, good thermal shock resistance, and at high temperature and graphite PuO2 compatible, was chosen for aerospace and nuclear fuel container materials thermoelectric devices for medical use. Iridium and it is used to grow high melting point alloy crucible oxide crystals, it can work in 2100 ~ 2200 ℃ for long and don't react with oxide materials. To save precious metals and reduce the cost of crystal growth, developed in recent years, several kinds of composite crucible, namely in the refractory metal molybdenum, tantalum, and tungsten crucible formed on a certain thickness of iridium or iridium layer, this kind of the service life of crucible co., LTD., widely used at low temperature.
In search of the material under the condition of high temperature and atmospheric temperature, the iridium rhenium tungsten, iridium, iridium hafnium, iridium, iridium rhodium molybdenum alloy etc for platinum thermoelectric potential, temperature coefficient of resistance, resistance rate, ultimate strength, elongation and the annealing temperature, the relationship between and instantaneous high temperature strength, hardness and until 2000 ℃ the volatile in the air are studied. Among them, iridium rhodium alloy is the most important iridium alloy, which is a continuous solid solution. With the increase of rhodium content, the density and hardness are decreased, the pressure processing performance is improved, and the anti-high temperature oxidation ability is enhanced. The thermoelectric potential of iridium rhodium alloy increases with the increase of rhodium. 1933 Ir/IrRh40 thermocouple, make the atmosphere until 2000 ℃ temperature measurement is possible. In addition, iridium tungsten alloy and iridium ruthenium alloy can also be used as thermocouple materials.
Iridium osmium alloy is a kind of peritectic, hard and brittle, which is very difficult to process. Iridium osmium alloy containing 30% ~ 70% osmium (atomic fraction) is a very good cathode coating material. Iridium osmium alloy is very hard and can also be used as pen tip and shaft tip material.
The escape work of iridium is 5. 4eV, thermionic emission is poor. After adding rare earth elements, the escape work of iridium can be reduced to 2. 5 ~ 2. 6 ev. Iridium cerium alloy has both high temperature strength and high emissivity. The hot anode made from this alloy can obtain high emission current density.
Nearly 50% of the total demand for iridium in the western world is used in the chemical industry, mainly for electrode materials, electrode coating materials and catalyst materials. It can also be used as solder (such as alloy of iridium nickel phosphorus) and heating wire (such as alloy of iridium ruthenium).
