Wear-resistant HfC_x film with infrared-visible compatible stealth property

Ultra-high temperature ceramic films have offered a combination of low infrared emissivity and durability in extremely harsh environments. However, desired applications have been limited by high visible light reflectivity. Herein, a novel strategy, by adjusting C stoichiometry and energy input, is proposed to construct a HfC_0.91 film consisted of HfC columnar nanograins with a width of 14.3 ± 0.4 nm and a-C phase at triple junctions, as well as exhibiting significantly increased surface roughness. The resulting microstructure simultaneously achieved excellent infrared-visible compatible stealth and tribo-mechanical properties. The infrared reflectivity/emissivity in the wavelength band of 8–14 μm is 0.9/0.1 primarily attributed to a reduction in lattice vibration absorption, while the low visible reflectivity (0.33) is mainly dominated by reduced plasma energy and enhanced multiple scattering absorption. Furthermore, the HfC_0.91 film exhibited improved wear-resistance due to the self-lubricating properties of a-C phase. Thus, this work offers a new strategy for designing wear-resistant HfC_x film with infrared-visible compatible stealth property for application in extreme thermo-mechanical service environments.