What is Hafnium in Welding?

Hafnium is a chemical element with the symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in many zirconium minerals. Its existence was predicted by Dmitri Mendeleev in 1869, though it was not identified until 1923, by Coster and Hevesy, making it the last stable element to be discovered. Hafnium is named after Hafnia, the Latin name for Copenhagen, where it was discovered.

What are the common uses of hafnium?

Hafnium is used in filaments and electrodes. A major development was the manufacture of practical hafnium metal by reduction of hafnium tetrachloride with magnesium metal in the Kroll process.

Hafnium is a good absorber of neutrons and therefore is used for control rods in nuclear reactors, even though its properties are similar to those of zirconium. The thermal neutron capture cross-section of hafnium is about 600 times that of zirconium.

Hafnium dioxide is used in infrared absorption spectroscopy. Some semiconductor fabrication processes use hafnium compounds as etchants and deposition precursors. Hafnium carbide is the most refractory binary compound known, with a melting point of 3890 °C. Hafnium is used in electronic devices such as dynamic random-access memories and microprocessors. Some superalloys used for special applications contain hafnium in combination with niobium, titanium, or tungsten.

Is hafnium an alloy?

No, hafnium is a pure element. However, it is often used as an alloying agent to improve the properties of other metals. For example, adding hafnium to steel increases its strength and resistance to corrosion.

What is the cost of hafnium?

The cost of hafnium metal is about $500 per kg.

How is hafnium recycled?

Hafnium can be recycled by breaking down used Hafnium-containing products and separating the Hafnium from other metals. The Hafnium can then be melted and formed into new products.