Novel (La0.2Eu0.2Nd0.2Sm0.2Pr0.2)(Al0.6Co0.4)O3-δ and (La0.2Eu0.2Nd0.2Sm0.2Ca0.2)(Al0.6Co0.4)O3-δ high-entropy ceramics with high emissivity and low degradation.

Novel (La 0.2 Eu 0.2 Nd 0.2 Sm 0.2 Pr 0.2)(Al 0.6 Co 0.4)O 3-δ (HE-1) and (La 0.2 Eu 0.2 Nd 0.2 Sm 0.2 Ca 0.2)(Al 0.6 Co 0.4)O 3-δ (HE-2) high-entropy ceramics were synthesized via solid-phase reaction technology. These two ceramics simultaneously own excellent infrared radiation performance and low degradation. The mechanism of emissivity enhancement was investigated, and emissivity decay of ceramics heated at 1500 °C for various holding time was studied. The results verify that the synthesized ceramics have perovskite crystal structure. The emissivity values of HE-1 and HE-2 are 0.78/0.66 and 0.82/0.83 in the near/mid-infrared band, respectively. These IR emissivity values are much higher than that of pure LaAlO 3 , which is attributed to enhanced impurity absorption, free carrier absorption and lattice vibration absorption. Moreover, after heating at 1500 °C for 10 h, HE-1 and HE-2 ceramics appear extremely slower emissivity decay rate (1.2–4.5 %), in comparison with fast decay rate (25.5–36.8 %) of pure LaAlO 3. This phenomenon can be attributed to the hysteresis diffusion effect of high-entropy ceramics, which can inhibit grain growth and emissivity decay. The novel ceramics have important application prospect in long-term energy-saving for high-temperature industry. [ABSTRACT FROM AUTHOR]