High-entropy La(Al0.2Co0.2Fe0.2Ni0.2Cr0.2)O3-d and La(Al0.2Co0.2Fe0.2Ni0.2Mn0.2)O3-d ceramics with broad-band high emissivity for long-term energy-saving

Abstract

Infrared radiation (IR) ceramics have been recognized as energy-saving materials for high-temperature industry due to excellent IR performance. However, for conventional IR ceramics, low emissivity in partial band and emissivity degradation during high-temperature service restricted the practical application. Herein, we integrated broad-band high emissivity and slow degradation rate in novel high-entropy perovskite ceramics: La(Al_0.2Co_0.2Fe_0.2Ni_0.2Cr_0.2)O_3−δ (HE-1) and La(Al_0.2Co_0.2Fe_0.2Ni_0.2Mn_0.2)O_3−δ (HE-2). Specifically, the high-energy ceramic HE-1 & HE-2 displayed high emissivity of 0.94/0.90 and 0.90/0.95 in the broad-band of near/mid-infrared (0.76–14 μm). This excellent IR performance can be attributed to impurity energy level absorption, free carrier absorption, and lattice vibration absorption. During high-temperature service, these high-entropy ceramics have much slower emissivity degradation rate than conventional IR ceramic, because of hysteresis diffusion effect. Additionally, energy-saving ratios of 17.70% and 10.77% were realized by heating water with porous burner containing HE-1 and HE-2 coating respectively, due to enhanced heat radiation in systems. Thus, these high-entropy IR ceramics have significant application potential for long-term energy-saving in high-temperature industry.