Tantalum hafnium carbide (Ta4HfC5) is a refractory compound with the highest melting point of all known compounds--4488 K (4215 °C, 7619 °F). It is the only known material that can not be welded with the atomic hydrogen welding method, which was developed by Irving Langmuir. As tantalum carbide and hafnium carbide, tantalum hafnium carbide is considered one of the hardest materials apart from the diamond.
Tantalum hafnium carbide (Ta4HfC5) is a refractory compound with the highest melting point of all known compounds--4488 K (4215 °C, 7619 °F). It is the only known material that can not be welded with the atomic hydrogen welding method, which was developed by Irving Langmuir. As tantalum carbide and hafnium carbide, tantalum hafnium carbide is considered one of the hardest materials apart from the diamond.