Laser-melting experiments in 2016 and 2018 established a melting point of 3,958–3,982 °C for binary HfC, surpassing tantalum carbide among binary compounds.
Usually carbon-deficient (HfC_x with x = 0.5–1.0) in the rock-salt crystal structure, it transitions from paramagnetic at x ≤ 0.8 to diamagnetic near stoichiometry.
Related hafnium carbonitride (HfCN) was experimentally shown in 2020 to withstand temperatures above 4,000 °C, making hafnium carbides premier candidates for hypersonic leading edges and rocket nozzles.