Hafnium alloy

Hafnium alloy contains the metal element hafnium, is the highest melting point in the world today. The substance with the highest known melting point is the compound of hafnium: tetratantalum pentacarbide hafnium (Ta4HfC5) has a melting point of 4215 degrees Celsius.

Introduce metal element hafnium is contained in hafnium alloy, it is the material with highest melting point on the world today. The substance with the highest known melting point is the compound of hafnium: tetratantalum pentacarbide hafnium (Ta4HfC5) has a melting point of 4215 degrees Celsius.

Chemical formula hafnium, metal Hf, atomic number 72, atomic weight 178.49, is a shiny silver-gray transition metal. There are six naturally stable isotopes of hafnium: hafnium 174, 176, 177, 178, 179, 180. Hafnium does not react with dilute hydrochloric acid, dilute sulfuric acid and strong alkali solutions, but is soluble in hydrofluoric acid and aqua regia. The element name comes from the Latin name for the city of Copenhagen. Swedish chemist Hewei xi and Dutch physicist Kest in 1925 with the method of fluoride salt classification crystallization of hafnium salt, and metal sodium reduction, get pure metal hafnium. Hafnium is found in 0.00045% of the earth's crust and is often associated with zirconium in nature.

Binary compounds tantalum carbide has the highest melting point (3983 °C) for binary compounds alone, although hafnium carbide is also one of the alloys with the highest melting point (3928 °C). Tantalum hafnium carbon alloy, which wikipedia says has the highest melting point of any known compound. Some people think that the high melting point of tantalum hafnium carbon alloy is caused by the composition change of compounds during the experiment. The role of hafnium in this process is merely to enhance the evaporation of carbon so that the melting point of the hafnium is comparable to that of tantalum carbide (with the evaporation of carbon, the stoichiometry of the components approaches that of tantalum carbide), and the high melting point of tantalum carbide results from the formation of a stable metal sublattice structure.

The difference of melting point values may be caused by the unavoidable changes of composition and structure of compounds and the lack of measurement methods in the process of high-temperature melting point measurement.