Synthesis and oxidation resistance of the high-entropy carbide HfZrAlCrTaC films prepared by reactive magnetron sputtering
| Parent link: | Ceramics International.— .— Amsterdam: Elsevier Science Publishing Company Inc. Vol. 51, iss. 21, pt. B.— 2025.— P. 35229-35235 |
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| مؤلفون آخرون: | , , , , |
| الملخص: | Title screen Ultra-high-temperature ceramics based on hafnium carbide and zirconium carbide are a unique class of materials that combine extreme thermomechanical properties with chemical stability, making them indispensable for use in ultra-high temperatures and aggressive environments. These materials exhibit a melting point exceeding 3000 °C, which exceeds most modern refractory compounds, as well as exceptional hardness (20–25 GPa) and Young's modulus (400–500 GPa). However, a key limitation of the widespread use of HfC and ZrC ceramics remains their tendency to catastrophic oxidation at temperatures above 500 °C. The introduction of elements such as aluminum or tantalum leads to the formation of glassy or fine-crystalline oxides during the oxidation process, characterized by low diffusion permeability for oxygen. The traditional alloying (5–10 at.%) often worsens the mechanical properties of the main carbide layer due to the formation of secondary phases and boundary defects. The conception of entropic stabilization of multicomponent carbides, where the introduction of five or more cations in equimolar ratios, leads to the formation of solid solutions with increased configurational entropy and suppression of secondary phases. However, existing works are mostly focused on alloying of ZrC and HfC with groups IV and V transition metals such as Ta, Nb, Ti, forming simple cubic carbide lattices, while the potential of alloying with aluminum and chromium, capable of forming protective Al2O3 and Cr2O3, remains poorly studied due to significant differences in their carbide lattices, requiring additional efforts to stabilize a single high-entropy lattice. Here we report the synthesis of the high-entropy system HfZrCrAlTaC, combining a refractory master carbide matrix Hf-Zr with oxidizing additives Al, Cr and Ta in close-to-equimolar compositions. The combination of entropic stabilization of the Hf-Zr matrix with Al and Cr additives overcomes the structural incompatibility of their carbides, effectively suppressing phase segregation. We found that HfZrCrAlTaC show increased oxidation resistance at 1100 °C, with the specific weight gain by 20 times compared to unalloyed HfZrC Текстовый файл AM_Agreement |
| منشور في: |
2025
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| الموضوعات: | |
| الوصول للمادة أونلاين: | https://doi.org/10.1016/j.ceramint.2025.05.225 |
| التنسيق: | الكتروني فصل الكتاب |
| KOHA link: | https://koha.lib.tpu.ru/cgi-bin/koha/opac-detail.pl?biblionumber=680730 |
| الملخص: | Title screen Ultra-high-temperature ceramics based on hafnium carbide and zirconium carbide are a unique class of materials that combine extreme thermomechanical properties with chemical stability, making them indispensable for use in ultra-high temperatures and aggressive environments. These materials exhibit a melting point exceeding 3000 °C, which exceeds most modern refractory compounds, as well as exceptional hardness (20–25 GPa) and Young's modulus (400–500 GPa). However, a key limitation of the widespread use of HfC and ZrC ceramics remains their tendency to catastrophic oxidation at temperatures above 500 °C. The introduction of elements such as aluminum or tantalum leads to the formation of glassy or fine-crystalline oxides during the oxidation process, characterized by low diffusion permeability for oxygen. The traditional alloying (5–10 at.%) often worsens the mechanical properties of the main carbide layer due to the formation of secondary phases and boundary defects. The conception of entropic stabilization of multicomponent carbides, where the introduction of five or more cations in equimolar ratios, leads to the formation of solid solutions with increased configurational entropy and suppression of secondary phases. However, existing works are mostly focused on alloying of ZrC and HfC with groups IV and V transition metals such as Ta, Nb, Ti, forming simple cubic carbide lattices, while the potential of alloying with aluminum and chromium, capable of forming protective Al2O3 and Cr2O3, remains poorly studied due to significant differences in their carbide lattices, requiring additional efforts to stabilize a single high-entropy lattice. Here we report the synthesis of the high-entropy system HfZrCrAlTaC, combining a refractory master carbide matrix Hf-Zr with oxidizing additives Al, Cr and Ta in close-to-equimolar compositions. The combination of entropic stabilization of the Hf-Zr matrix with Al and Cr additives overcomes the structural incompatibility of their carbides, effectively suppressing phase segregation. We found that HfZrCrAlTaC show increased oxidation resistance at 1100 °C, with the specific weight gain by 20 times compared to unalloyed HfZrC Текстовый файл AM_Agreement |
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| DOI: | 10.1016/j.ceramint.2025.05.225 |