Hafnium carbide powder (HfC) is a chemical compound of hafnium and carbon. With a melting point of about 3900 °C, it is one of the most refractory binary compounds known. Hafnium carbide powder is a very hard material. It is used in hard coatings. It is also used as rocket nozzle throat material and in metal-ceramic materials. It has low oxidation resistance, with the oxidation starting at temperatures as low as 430 °C.

Hafnium carbide powder is ductile and has a brilliant silver luster. The metal has a close-packed hexagonal crystal structure. It exhibits excellent mechanical properties and has extremely good corrosion resistance. The electronics industry uses a hafnium-based compound that can be employed in gate insulators in the 45 nm generation of integrated circuits.

Hafnium carbide-based compounds are practical high dielectrics, allowing reduction of the gate leakage current which improves performance at such scales. Also, Due to its heat resistance and its affinity to oxygen and nitrogen, hafnium is a good scavenger for oxygen and nitrogen in gas-filled and incandescent lamps. Hafnium is also used as the electrode in plasma cutting because of its ability to shed electrons into air.

Hafnium carbide is the most refractory binary compound known to man. Similarly, hafnium nitride (HfN) is the most refractory nitride known with a melting point of approximately 3305 °C. Hafnium carbide powder is used in hard coatings, often applied by processes such as plasma spraying.

Hafnium carbide powder (HfC) is one example of advanced ceramic fiber matrices. It is a compound with the highest known melting temperature: 3890C. In theory, a part made with Hafnium Carbide fiber-matrix composite would survive temperatures that would soften or melt even refractory metal-metal alloys such as rhenium-tungsten blends. HfC has about 60 percent the density of metal alloys, so critical rocket, missile and aerospace components made with HfC composites would be correspondingly lighter.