Entropy-Assisted High-Entropy Oxide with a Spinel Structure toward High-Temperature Infrared Radiation Materials

Abstract

Developing advanced materials with a high-entropy concept is one of the hot trends in materials science. The configurational entropy of high-entropy materials can be tuned by introducing different atomic species, which can also impart a result in excellent physical and chemical properties. In this work, we synthesized a solid-solution oxide (Cu, Mn, Fe, Cr) 3 O 4 by a simple and scalable solid-phase synthesis method. We extensively investigated the microstructure and chemical composition, indicating that (Cu, Mn, Fe, Cr) 3 O 4 has a single-phase spinel structure. Simultaneously, we reasonably evaluated the position occupied by the elements of (Cu, Mn, Fe, Cr) 3 O 4 in a spinel structure as (Cu 0.75 Fe 0.25 )(Fe 0.25 Cr 0.375 Mn 0.375 ) 2 O 4 . Here, we first evaluated the infrared radiation performance of (Cu, Mn, Fe, Cr) 3 O 4 . The new, high-entropy oxide (HEO) (Cu, Mn, Fe, Cr) 3 O 4 powder exhibits high infrared emissivity values of 0.879 and 0.848 in the wavelengths of 0.78−2.5 and 2.5−16 μm, respectively, and has excellent thermal stability. More importantly, the infrared emissivity values of as-prepared HEO coating reach 0.955 (0.78−2.5 μm) at room temperature and 0.936 (3−16 μm) at 800 °C. This work provides a viable strategy toward the laboratory mass production of this HEO for infrared radiation materials, which shows great potential in the energy-related applications.

Design Strategies for Perovskite-Type High-Entropy Oxides with Applications in Optics

“…In addition, the transition elements (Cr, Mn, Fe, and Co, etc.) are prone to impurity energy levels, which are detrimental to the improvement of optical reflectivity . After considering these factors, we restricted the A-site element range (+1: Li, Na, and K; +2: Ca, Sr, and Ba; +3: La).…”

“…are prone to impurity energy levels, which are detrimental to the improvement of optical reflectivity. 25 After considering these factors, we restricted the A-site element range (+1: Li, Na, and K; +2: Ca, Sr, and Ba; +3: La). Then, for geometric stability, the Goldschmidt tolerance factor enables a preliminary determination of geometric stability (Equation S1), which implies that the material system has the same probability of being a perovskite structure for the same value of t. In fact, the degree of lattice distortion also affects the probability of formability, which can be further described by the lattice difference (Equation S2).…”

“…For instance, Guo et al reported a spinel-structure high-entropy oxide (Cu, Mn, Fe, Cr extremely low optical reflectivity values, which can reach 4.5% in the wavelengths of 0.78−2.5 μm. 25 O 19 with a superior thermal emissivity in the 3 to 14 μm range, which can be attributed to introduction of rare-earth elements with surplus f electrons. 26 According to the charge balance principle, Qiu et al designed and prepared a medium-entropy ceramics, (Ta,-Ti) 0.1 (Zr,Hf,Ce) 0.9 O 2 , with excellent high-temperature thermal radiation shielding performance through Ta 5+ substituting for Me 4+ .…”

Design and Development of High-Entropy Alloys with a Tailored Composition and Phase Structure Based on Thermodynamic Parameters and Film Thickness Using a Novel Combinatorial Target

“…High-entropy alloys (HEAs) have attracted significant interest and emerged as a new research area since they were first reported in 2004 by Cantor et al and Yeh et al − HEAs have at least five elements, each with a similar accommodating probability in a crystal lattice site . The existence of numerous mixing elements in HEAs favors a high configurational entropy. , Surprisingly, even with this novel concept in alloy development, researchers have managed to produce only solid solutions (SS) of various HEAs prepared thus far. Moreover, after the commercial use of alloys, the most advanced type of alloy development has become a subject of debate regarding overcoming the limitations of conventional alloys (CAs) that can be used in a wide range of applications, e.g., biomedical and energy sector, and making them environment friendly .…”

“…The existence of numerous mixing elements in HEAs favors a high configurational entropy. , Surprisingly, even with this novel concept in alloy development, researchers have managed to produce only solid solutions (SS) of various HEAs prepared thus far. Moreover, after the commercial use of alloys, the most advanced type of alloy development has become a subject of debate regarding overcoming the limitations of conventional alloys (CAs) that can be used in a wide range of applications, e.g., biomedical and energy sector, and making them environment friendly . Some prominent features distinguishing HEAs from CAs in a wide temperature range include sluggish diffusion, lattice distortion, high mixing entropy, and cocktail effect .…”