Key Takeaways & Executive Findings
- •• • Non-equimolar (Zr0.2Ti0.2Ta0.3Cr0.3)C achieves superior oxidation resistance up to 2500 °C, with a dense oxide layer that suppresses mass gain and spallation, outperforming equimolar compositions. • • Laser-assisted screening at 2500 °C identified Cr as the critical element; tuning Cr ratio from 0.25 to 0.3 in the equimolar base (Zr0.25Ti0.25Ta0.25Cr0.25)C led to optimal performance, demonstrating the importance of compositional engineering. • • The protective oxide scale consists of molten (Cr, Me)(Ta, Me)O4 and (Ta, Me)2O5 phases embedded with (Zr, Me)O2 crystals, which seal defects and enhance thermal stability, providing a mechanistic basis for superior oxidation resistance. • • The self-developed laser oxidation platform enables rapid, high-throughput screening of HEC compositions at 2500 °C, accelerating the discovery of oxidation-resistant materials for ultrahigh-temperature applications.
Abstract
High-entropy carbides (HECs) are promising candidates for ultrahigh-temperature applications, but their oxidation resistance at temperatures above 2000 °C remains a critical bottleneck. Here, we report a laser-assisted compositional engineering strategy to develop non-equimolar (Zr0.2Ti0.2Ta0.3Cr0.3)C HECs with superior oxidation resistance up to 2500 °C. Using a self-developed laser oxidation platform, we first screened equimolar (Zr0.25Ti0.25Ta0.25Me0.25)C (Me = Hf, W, Nb, Cr, V, Mo) samples at 2500 °C, identifying Cr as a critical element for forming protective oxide scales. Systematic tuning of Cr content revealed that the optimal composition (Zr0.2Ti0.2Ta0.3Cr0.3)C exhibits a dense, crack-free oxide layer composed of molten (Cr, Me)(Ta, Me)O4 and (Ta, Me)2O5 phases embedded with (Zr, Me)O2 crystals, which effectively seal defects and suppress oxygen diffusion. The synergistic effects of these phases lead to a significant reduction in mass gain and oxide layer thickness compared to equimolar counterparts. This work provides a new pathway for designing HECs with long-life oxidation resistance at 2500 °C, enabling their use in extreme environments such as hypersonic vehicle leading edges and rocket nozzle throats.
1. Introduction
High-entropy carbides (HECs) have emerged as promising candidates for ultrahigh-temperature applications, yet their oxidation resistance above 2000 °C remains a critical bottleneck. Conventional HECs, such as (Hf0.2Ta0.2Zr0.2Ti0.2Nb0.2)C, exhibit parabolic oxidation kinetics up to 1500 °C, but at higher temperatures, they form porous and loose oxide layers that accelerate degradation. For instance, Backman et al. observed detrimental oxide scales at 1700 °C, and Wang et al. reported deteriorated resistance at 1100 °C for Cr-containing HECs. These failures stem from the inability of oxide scales to remain dense and adherent under extreme thermal gradients and mechanical stress. Consequently, there is an urgent need for HEC compositions that can form self-healing, defect-sealing oxide layers at temperatures approaching 2500 °C.
This study introduces a laser-assisted compositional engineering strategy to address this bottleneck. By utilizing a self-developed laser oxidation platform, we rapidly screen a series of equimolar HECs at 2500 °C, identifying Cr as a critical element for forming protective oxide phases. Systematic tuning of Cr content leads to the discovery of non-equimolar (Zr0.2Ti0.2Ta0.3Cr0.3)C, which exhibits superior oxidation resistance due to the synergistic formation of molten (Cr, Me)(Ta, Me)O4 and (Ta, Me)2O5 phases embedded with (Zr, Me)O2 crystals. This oxide architecture effectively seals defects and suppresses oxygen diffusion, providing a new pathway for designing HECs with long-life performance at ultrahigh temperatures.
Loading authentic research manuscript (Pages 1–5)...
Zihao Wen, Yuhui Chen, Lei Zhuang, Hulei Yu, Yanhui Chu (2026). Laser-assisted compositional engineering of high-entropy carbides with superior oxidation resistance at 2500 °C. SCIENCE CHINA Materials. https://doi.org/10.1007/s40843-025-3508-3
Research & Educational Purpose Only: The translations, structured abstracts, analytical annotations, and data reports provided by SinoGreenTechare intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoGreenTech claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is the maximum operating temperature for the developed (Zr0.2Ti0.2Ta0.3Cr0.3)C HEC, and how does it compare to existing HECs?
The developed HEC exhibits superior oxidation resistance up to 2500 °C, which is significantly higher than previously reported HECs that typically operate below 1700 °C. For example, (Hf0.2Ta0.2Zr0.2Ti0.2Nb0.2)C shows parabolic oxidation up to 1500 °C but forms porous scales at 1700 °C. Our composition maintains a dense, protective oxide layer at 2500 °C, as demonstrated by laser oxidation tests.
How does the laser-assisted screening platform accelerate the discovery of oxidation-resistant HECs?
The self-developed laser oxidation platform allows rapid, high-throughput testing of multiple HEC compositions at 2500 °C, reducing the time and cost compared to conventional furnace oxidation tests. This enables systematic screening of equimolar and non-equimolar compositions, leading to the identification of Cr as a critical element and the optimal composition (Zr0.2Ti0.2Ta0.3Cr0.3)C.
What are the underlying mechanisms for the superior oxidation resistance at 2500 °C?
The superior resistance is attributed to the formation of a dense oxide scale composed of molten (Cr, Me)(Ta, Me)O4 and (Ta, Me)2O5 phases embedded with (Zr, Me)O2 crystals. These phases synergistically seal defects and cracks, preventing oxygen diffusion and enhancing thermal stability. The molten phases provide a self-healing effect, while the crystalline (Zr, Me)O2 acts as a structural reinforcement.
How does the Cr content affect the oxidation resistance, and what is the optimal ratio?
Cr is critical for forming the protective oxide phases. In equimolar (Zr0.25Ti0.25Ta0.25Cr0.25)C, oxidation resistance is improved but not optimal. By increasing Cr to 0.3 and adjusting other elements to (Zr0.2Ti0.2Ta0.3Cr0.3)C, the oxide layer becomes more effective, likely due to enhanced formation of the molten phases. The optimal Cr ratio is 0.3, as demonstrated by superior performance at 2500 °C.
What are the potential applications and scalability of this HEC?
This HEC is suitable for ultrahigh-temperature applications such as rocket nozzles, hypersonic vehicle leading edges, and thermal protection systems. The laser-assisted screening method is scalable for laboratory research, but industrial production would require conventional sintering techniques. The composition can be synthesized using standard powder metallurgy methods, making it feasible for large-scale manufacturing.
Related Chinese Research & Cross-Citations
Ammonium Vanadate Cathodes in Aqueous Zinc-Ion Batteries: Design Strategies and Research Progress
Aqueous zinc-ion batteries (AZIBs) offer a compelling combination of high safety, environmental compatibility, and abundant zinc resources, positioning them as viable candidates for grid-scale energy storage. Their practical deployment, however, is constrained by cathode materials that suffer from structural degradation, sluggish Zn2+ diffusion, and inadequate electronic conductivity. Ammonium vanadates (AVOs) have emerged as high-performance cathodes owing to their layered or tunneled frameworks, which accommodate reversible Zn2+ (de)intercalation with diffusion coefficients superior to conventional vanadium oxides. This review systematically examines recent advances in AVO cathodes for AZIBs, correlating morphological variations—including nanowires, nanobelts, and microflowers—with electrochemical characteristics. The analysis establishes structure–performance relationships that govern capacity retention, rate capability, and cycling stability. Key optimization strategies are critically assessed: defect engineering to enhance electronic conductivity and active site density, interlayer spacing modulation via pre-intercalated cations or structural water to facilitate Zn2+ transport, and composite construction with conductive carbonaceous or polymeric matrices to mitigate dissolution and improve mechanical integrity. Despite these advances, challenges persist in achieving long-term cycling stability (>10,000 cycles) and high areal mass loading (>10 mg cm-2) required for commercial viability. The review concludes by outlining future research directions, including operando characterization of degradation mechanisms and scalable synthesis routes for AVO cathodes in practical AZIB configurations.
Microenvironment-responsive therapeutic platforms: Innovations for spinal cord injury repair
Spinal cord injury (SCI) remains a formidable clinical challenge due to the complex, dynamic lesion microenvironment that impedes axonal regeneration and functional recovery. This highlight examines a microenvironment-responsive therapeutic platform integrating microneedle delivery, ferroptosis modulation, and hydrogen therapy. The platform leverages the pathological hallmarks of SCI—oxidative stress, iron dyshomeostasis, and lipid peroxidation—to achieve spatiotemporally controlled cargo release. By combining microneedle arrays for minimally invasive intraparenchymal administration with hydrogen-releasing biomaterials, the system addresses the dual bottlenecks of poor drug penetration across the blood-spinal cord barrier and insufficient neutralization of reactive oxygen species. Ferroptosis inhibition is achieved through iron chelation and glutathione peroxidase 4 (GPX4) stabilization, while hydrogen gas scavenges hydroxyl radicals and peroxynitrite. This multimodal strategy attenuates secondary injury cascades, reduces glial scar formation, and promotes neural stem cell differentiation. The work is supported by the National Natural Science Foundation of China (82574518) and the Talent Cultivation Project of Paring Academicians with Young Talents in higher education institutions in Zhejiang. The authors declare no conflict of interest. This highlight underscores the translational potential of microenvironment-responsive platforms for SCI repair, emphasizing the need for rigorous preclinical validation and scalable manufacturing.
Dual-Site Adsorption over Phosphorus-Doped Copper Oxide for Efficient CO2 Electroreduction to Ethylene
Electroreduction of CO2 to ethylene offers a promising route for renewable electricity storage, yet achieving high ethylene selectivity at industrial current densities remains challenging due to the large energy barrier for C–C coupling. Here, we report a “MOF-assisted in situ doping” strategy to introduce the oxophilic nonmetal phosphorus (P) into the copper oxide (CuO) lattice, constructing a localized Cu–P dual-site adsorption configuration for the key *OCCHO intermediate. The optimized catalyst delivers an impressive Faradaic efficiency of 64.6% for ethylene with a partial current density of 646 mA cm-2. Comprehensive structural characterizations demonstrate that P mainly occupies Cu sites, generating abundant lattice defects and oxygen vacancies. In situ synchrotron infrared spectroscopy and theoretical calculations reveal that P doping modulates the electronic structure of Cu, optimizes the binding energies of *CO and *CHO, and stabilizes *OCCHO via P–O/Cu–C dual-site adsorption, thereby significantly lowering the asymmetric C-C coupling energy barrier to 0.74 eV. This work highlights a dual-site microenvironment regulation strategy for CO2-to-ethylene electroreduction.
Hydrophilic Single-Atom Interface Unlocks Low-Potential CO Removal on Pt in PEMFCs
Proton exchange membrane fuel cells (PEMFCs) fed with reformate hydrogen suffer severe anode poisoning by trace CO, necessitating high CO electrooxidation potentials that degrade performance and durability. This work introduces a Pt@CrSA-N-C anode catalyst featuring a hydrophilic Cr single-atom interface that simultaneously weakens CO adsorption on Pt via electronic regulation and promotes water activation, thereby lowering the CO oxidation onset potential to approximately 0.13 V vs. RHE. The onset potential was determined by two independent methods: the first potential at which the background-corrected current exceeds 0 mA cm-2 during CO oxidation reaction tests in a three-electrode system, and the potential at which the forward scan current exceeds the N2 background current in CO-stripping voltammetry. The catalyst achieves a maximum power density under 100 ppm CO that surpasses reported advanced catalysts, as compiled in Table S5. Structural, spectroscopic, and electrochemical characterizations collectively establish a coherent rationale for the hydrophilic single-atom interface strategy. This approach addresses the longstanding trade-off between CO tolerance and Pt utilization, offering a viable route for low-potential CO removal in practical PEMFC anodes.
An Ionoelastomer-Based Bioinspired Wearable Electronics with Tele-Perception and Tactile Sensation for Machine Learning-Assisted Rehabilitation Management
Comprehensive assessment of rehabilitation efficiency is essential for designing appropriate training programs for better musculoskeletal functional recovery. Existing contact-receptor-dependent rehabilitation assessment systems mostly focus on assessing the restoration of muscle function by evaluating grip strength or joint flexion angle; however, parameters reflecting neuromuscular synergistic function are always overlooked. Herein, we develop an ionoelastomer-based soft artificial electroreceptor (SAER) that integrates tele-perception and tactile sensation to track the rehabilitation process, collecting signals related to approaching speed and grip strength sequentially. The SAER uses polyurethane ionoelastomer incorporated with quasi-solid conductive salt as the electric field receptor, and is integrated on a rehabilitation-training ball after assembly to establish an untethered detection device; this enables the remote capture of hand approaching parameter within a 9 cm range, followed by the quantification of grip strength when contacting and grasping. Furthermore, a data-driven assessment system is established by integrating machine learning, which accurately classifies rehabilitation efficiency into six levels; it supports for rehabilitation evaluation and training programs adjustment. Overall, the SAER-based rehabilitation management system establishes a paradigm that synergistically evaluating parameters corresponding to neuromuscular functional restoration and holds strong potential for home-based active rehabilitation for minimizing dependence on frequent clinical supervision.
Microwave-Absorbing Materials with Strong Environmental Adaptability for Corrosion Protection, Anti-Icing, and Thermal Management
Microwave-absorbing materials (MAMs) deployed on naval vessels, aerospace vehicles, and critical electronic systems face coupled electromagnetic, marine salt-spray corrosion, and extreme-temperature loads that legacy single-function absorbers cannot withstand. This review consolidates progress on three environmentally adaptive MAM classes: corrosion-protective, anti-icing, and thermal-management absorbers. The electromagnetic loss and impedance-matching fundamentals are first established, then the synergistic mechanisms, design strategies, and characterization protocols for each class are examined against representative material systems and their measured performance. The analysis identifies a shared design logic—multiscale hierarchical architecture, interfacial polarization engineering, and multifunctional phase integration—while distinguishing the divergent protection mechanisms: barrier and passivation effects for corrosion, surface-energy and latent-heat regulation for anti-icing, and phonon–electron transport decoupling for thermal management. Persistent bottlenecks include the trade-off between impedance matching and protective-layer density, the absence of standardized coupled-field test protocols, and the scarcity of long-term salt-spray and thermal-cycling durability data. Future directions are delineated: intelligent self-adaptive absorbers, multiphysics-coupled simulation frameworks, and environmentally benign multifunctional integration. The review provides a theoretical and technical basis for the design, construction, and engineering scale-up of next-generation high-performance absorbers for aerospace, electronic, and marine equipment.