Hafnium

It can be prepared by reducing hafnium tetrachloride with magnesium or by thermally decomposing hafnium tetriodide. HfCl4 and K2HfF6 can also be used as raw materials. It is produced by electrolysis in a NaCl-KCl-HfCl4(or K2HfF6) melt, and the process is similar to that of the electrolytic production of zirconium.

Hafnium mostly coexists with zirconium and there is no hafnium raw material that exists alone. At present, the raw material for manufacturing hafnium is crude hafnium oxide separated in the process flow of manufacturing zirconium. Hafnium oxide is extracted by the method of ion exchange resin, and then metallic hafnium is prepared from this hafnium oxide by the same method as zirconium.

Hafnium is very useful because it emits electrons easily (such as being used as the filament of incandescent lamps). Hafnium is used as the cathode of X-ray tubes, and alloys of tungsten or molybdenum are used as electrodes of high-voltage discharge tubes. It is commonly used as the cathode for X-rays and in the tungsten wire manufacturing industry. Pure hafnium is malleable, easy to process, resistant to high temperatures and corrosion, and is an important material in the atomic energy industry. Hafnium has a large thermal neutron capture cross-section and is an ideal neutron absorber. It can be used as a control rod and protective device in atomic reactors. Hafnium powder can be used as a rocket thruster. In the electrical industry, the cathode of X-ray tubes can be manufactured. Hafnium alloys can be used as the front protective layer for rocket nozzles and gliding re-entry vehicles. Hafnium-tantalum alloys can be used to manufacture tool steel and resistance materials. Hafnium is used as an additive element in heat-resistant alloys. For instance, hafnium is added to some alloys of tungsten, molybdenum and tantalum. Hafnium carbide, due to its high hardness and melting point, can be used as an additive for hard alloys. The melting point of 4TaCHfC is approximately 4215℃, making it the compound with the highest known melting point. Hafnium can be used as an air-absorbing agent in many inflation systems. Hafnium getter can remove oxygen, nitrogen and other unwanted gases present in the system. Hafnium is often used as an additive in hydraulic oil to prevent the evaporation of hydraulic oil during high-risk operations. It has strong anti-volatility properties. Due to this characteristic, it is generally used in industrial hydraulic oil and Medical hydraulic oil.