Oxidation behavior of (Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)C high-entropy ceramics at 1073-1473 K in air

High-temperature toughening in ternary medium-entropy (Ta1/3Ti1/3Zr1/3)C carbide consolidated using spark-plasma sintering

“…This is a feature that is known if one uses WC or VC in ternary carbide alloys [18]. In addition, for high-entropy ceramics, the layer-by-layer oxidation behavior of the highentropy ceramics have been reported [19], suggesting that upon reheating to elevated temperatures, the different diffusion rates for metal and carbon atoms in the pure metals or carbides [4] may lead to localization or decomposition of the complex solid-solution such as medium-entropy or high-entropy ceramics.…”

Fine-grained dual-phase high-entropy ceramics derived from boro/carbothermal reduction

“…In the last two to three years, high-entropy ceramics have become a major global research emphasis. Different series of high-entropy ceramics, such as silicides [2,3], oxides [1,4], nitrides [5], carbides [6][7][8][9], and borides [10][11][12][13] have been widely studied. The subject of high-entropy boride (HEB) and high-entropy carbide (HEC) ceramics are, so far, the most intensively researched.…”

“…Yan et al [6] have synthesized (Hf 0.2 Zr 0.2 Ta 0.2 Nb 0.2 Ti 0.2 )C by spark plasma sintering (SPS), which showed much lower thermal diffusivity and conductivity than the binary carbides like HfC, ZrC, TaC, and TiC. In prior work, most of the HEC and HEB ceramics were fabricated through the use of blends of commercially available single boride or carbide powders, and subsequent in-situ HEB or HEC formation during densi cation [6,[8][9]. As an alternative, high-entropy ceramics can be prepared and sintered using highentropy powders derived by the boro/carbothermal reduction approach, using metal oxides as powder precursors.…”

A step forward from high-entropy ceramics to compositionally complex ceramics: a new perspective

“…The high-entropy borides and carbides are being examined for their potential use as nextgeneration UHTCs [118,119]. These classes of materials have also shown increased mechanical properties [56,61,62,64,66] and oxidation resistance [48,63,120,121] Notably, a general property of HECs is represented by the increased hardness in comparison with the RoM averages, which have been reported for high-entropy borides [48,50,54,56], carbides [59,61,63,66], and silicides [44,45]. Further discussion can be found in the next section.…”