High-entropy (CrCoFeMnNi)3O4 ceramic with high emissivity for energy saving

The development of infrared radiation materials, which combine high emissivity, excellent thermal stability, and low cost, is vital for energy-efficient operation in high-temperature industrial settings. Non-oxide high-emissivity materials are susceptible to oxidation at elevated temperatures, resulting in degradation of emissivity; Oxide-based high-emissivity materials offer superior stability in high-temperature environments, but often exhibit inadequate emissivity. In this study, a high-entropy spinel ceramic, (CrCoFeMnNi) 3 O 4 (HES), was synthesized via a cost-effective solid-state method. The HES ceramic exhibited high emissivity of 0.875 in the wavelength range of 0.76–2.5 μm and 0.861 in the wavelength range of 2.5–14 μm. Moreover, it demonstrated excellent thermal stability following heat treatment at 1300 °C for 30 h in air. Applied as a coating to corundum crucibles, HES coating elevated the internal equilibrium temperature by more than 42 °C and increased the heating rate from 2.65 to 2.89 °C/min. These findings demonstrate the promising potential of HES ceramic for next-generation thermal management coating in energy-intensive industries such as metallurgy, ceramics manufacturing, and high-temperature processing.