The irradiation stability of Cr-based protective coatings on zirconium alloys is critical for the development of accident-tolerant fuel claddings. However, conventional surface irradiation often produces shallow, nonuniform damage, obscuring interfacial behavior. In this study, we perform cross-sectional He2+ irradiation to directly examine the interfacial response and He bubble evolution across Cr monolayer and Cr/CrAlSiN multilayer coatings on Zr substrates. Irradiation was carried out at 500 and 750 degrees C to doses of 2-3 displacements per atom (dpa), enabling a direct comparison of temperature-dependent microstructural evolution. In the Cr monolayer, He implantation produced a homogeneous distribution of nanoscale bubbles throughout the damaged region and large cavities at the Cr/Zr interface, indicating severe Kirkendall-type voiding and interfacial decohesion at elevated temperature. In contrast, the Cr/CrAlSiN multilayer exhibited a periodically modulated bubble distribution, with bubble fragmentation and transformation into nanoscale platelets at CrAlSiN interfaces. A N-enriched Zr(N) interlayer formed spontaneously at the CrAlSiN/Zr interface, effectively suppressing bubble accumulation and interdiffusion. The nanochannel interfaces acted as He sinks and diffusion barriers, enhancing interfacial bonding and mitigating swelling. This work demonstrates that cross-sectional ion irradiation is a powerful approach for probing interfacial stability in multilayer systems, offering new insights into He-defect interactions and radiation tolerance engineering at buried interfaces. The findings highlight the potential of Cr/CrAlSiN multilayers as advanced coating architectures for high-temperature nuclear environments. (c) 2026 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

In this study, the effects of nano Si modification and dissolved oxygen concentration on the corrosion behavior of precursor-derived SiC and CVD SiC were investigated in static lead-bismuth eutectic (LBE) at 500 degrees C. The introduction of nano Si enhanced the corrosion resistance of precursor-derived SiC. Specifically, nano Si acted as an in-situ C trap, consuming free C to promote SiC grain growth, enhance densification, and reduce the grain boundary density. A more pronounced SiO2-rich region was also observed in nano Si-modified SiC. Under oxygen-controlled conditions, SiC experienced mild dissolution corrosion. In contrast, under oxygen-saturated environments, SiC suffered severe oxidation-coupled intergranular degradation via preferential O diffusion and Pb penetration. Notably, the microstructural optimization effectively inhibited the diffusion and attack of O and Pb along grain boundaries. Furthermore, the transgranular fracture of CVD SiC was associated with its coarse-grained structure and chemical weakening by the corrosive medium.

This study focused on the early-stage corrosion behavior of the Al2O3 coatings. Al2O3 coatings were deposited on SIMP steel substrates via magnetron sputtering. Subsequent corrosion experiments were conducted in oxygen-saturated lead-bismuth eutectic (LBE) at 500 degrees C for 300 h and 500 h, and 600 degrees C for 300 h, with complementary testing under an oxygen-controlled condition (10-6 wt.%) at 500 degrees C for 500 h. The coating exhibited an initial thickness increase after 300 h at 500 degrees C in oxygen-saturated LBE, followed by a decrease after 500 h. In contrast, under the oxygen-controlled condition, the coating thickness remained nearly unchanged throughout the 500 h exposure. This divergence is attributed to the initial formation and decomposition of PbAl2O4 in oxygen-saturated environment, whereas formation of PbAl2O4 was suppressed under oxygen-controlled condition. The coating's maintained corrosion resistance despite phase changes confirms the efficacy of oxygen control and its promise for structural material applications.

Maximizing fracture toughness is a challenge for structural ceramics operating in extreme environments. This work proposes a structural editing strategy that harnesses atomic-scale [M-X] sublayer substitution coupled with secondary-phase in situ formation to tailor the hierarchical architecture of MAX phase ceramics. During reactive sintering, the Zr2SeB parent phase transforms into a more stable Zr2SeC variant, with plate-like ZrB2 reinforcements nucleating and growing along MAX phase grain boundaries. Precise control over the aspect ratio and spatial distribution of metal boride is achieved by tuning heterogeneous nucleation and diffusion-mediated growth, establishing a dual-scale hierarchy in crystal and morphology. This designed microstructure is found to activate synergistic toughening mechanisms, mainly crack deflection and grain pull-out, which contribute to the improved fracture toughness of the ceramics. These findings indicate that atomic-level manipulation can support the rational design of MAX phase composites with optimized architecture-property correlations.

Abstract High-temperature molten salt systems are essential for energy storage and molten salt reactors, but their corrosiveness limits the durability of structural materials. MAX phases offer excellent high-temperature stability and oxidation resistance, yet the selective dissolution of A-site atomic layers in molten salts leads to structural degradation. Here, by introducing high-oxidation-potential non-noble metal Cu into the A-site, we enhanced interlayer bonding and suppressed A-site dissolution. Using V2SnC as a model, corrosion tests in MgCl2−NaCl−KCl molten salt at 700 °C showed that Cu incorporation transformed the corrosion behavior from mass loss (5.46% for V2SnC) to mass gain (4.80% for V2(Sn0.7Cu0.3)C) and drastically reduced the corrosion rate by 89.8%. Mechanistic analysis revealed that Cu inhibits Sn dissolution and volatile SnCl4 formation, strengthens M-A bonding, and promotes a dense MgO protective layer. Electrochemical measurements further confirmed enhanced corrosion resistance, with self-corrosion potential shifting positively and induced current density decreasing significantly. This work provides a cost-effective strategy to improve MAX phase structural stability in molten salt environments, advancing their application in high-temperature systems.

Sintered SiC was pre-irradiated with 1.52 MeV protons and subsequently exposed to oxygen-controlled LBE (500 degrees C, 10-7wt.% O, 1500 h). The irradiation greatly accelerated the corrosion of SiC in LBE, as the mass loss of the irradiated specimen increased by an order of magnitude. A 1.29 & micro;m thick and Si-enriched corrosion layer formed on the surface, mixed with some (Pb, Bi) O inclusions and cavities. It was observed that the SiC proceeded via dissolution caused by chemisorption of Pb, Bi on the surface, and intergranular corrosion occurred preferentially along the C-rich grains. The corrosion mechanism was more evident, for the irradiation produced locally disordered Si-C bonds and enhanced electrochemical activity, further promoting the chemisorption and diffusion of Pb/Bi.

Liquid lead-bismuth eutectic (LBE) corrosion represents a significant challenge for structural materials in leadcooled fast reactors. Despite the potential of MAX phases, the fundamental mechanisms governing their corrosion resistance, particularly the role of M-site elements beyond oxide formation, remain to be fully elucidated. This study investigates the corrosion behavior of MAX phases with M-site refractory metals (Hf, Ta, Nb) in oxygencontrolled LBE, revealing a competitive kinetic process between Al outward diffusion and O inward penetration. We propose a dual regulatory mechanism of M-site elements: weak M-Al bonding tends to promote Al vacancy formation, thereby facilitating O ingress, while high oxygen affinity seems to suppress both O permeation and Al efflux by trapping oxygen within the lattice. This mechanism helps explain why Ta2AlC forms dense, crack-free scales, in contrast to the severe cracking observed in Nb2AlC. By leveraging the high oxygen affinity of Hf, the multicomponent (Hf,Nb,Ta)2AlC achieved optimal corrosion resistance among the tested samples. Our results suggest a design criterion for M-site engineering, highlighting the importance of oxygen affinity in mitigating corrosion for next-generation nuclear materials.

Introducing SiC nanowires into SiC fiber-reinforced SiC matrix (SiCf/SiC) composites is an effective multiscale reinforcement strategy. In this study, nickel acetate tetrahydrate (Ni(Ac)2·4H2O) was incorporated into a liquid polycarbosilane (LPCS) and converted stepwise into metallic Ni and Ni₂Si during pyrolysis. However, transmission electron microscopy and oxidation test indicated that the resulting fibrous products were mainly carbon nanotubes (CNTs). To obtain SiC nanowires, additional nano Si was introduced into LPCS containing Ni(Ac)2·4H2O, with EDS and TEM confirming their successful formation. Furthermore, the introduction of nano Si yielded SiC with larger grain size compared to that derived from pure LPCS or LPCS containing Ni(Ac)2·4H2O. To evaluate the impact of these changes on the mechanical properties of SiC matrix composites, SiCf/SiC composites were prepared using the impregnation-pyrolysis process with two types of LPCS as raw materials: one containing nano Si and the other containing both Ni(Ac)2·4H2O and nano Si. The resulting composites exhibited flexural strengths of 285 ± 32 MPa and 577 ± 52 MPa, respectively. The improved flexural strength of the latter was explained by the presence of SiC nanowires.

ABSTRACT The corrosion behavior of MAX phases in molten chloride salts remains a critical limitation for their deployment in advanced nuclear and high‐temperature energy systems. Here, the corrosion mechanisms of Ti 2 SC, Ti 2 AlC, Hf 2 SC, and Hf 2 SB were systematically investigated in molten MgCl 2 –NaCl–KCl at 700°C under vacuum by combining static corrosion experiments with density functional theory (DFT) calculations. Ti 2 SC exhibited the highest corrosion resistance, maintaining relatively good structural integrity through the formation of a compact oxide‐rich corrosion product scale, whereas Hf 2 SB suffered catastrophic fragmentation and Hf 2 SC showed severe localized cracking. Ti 2 AlC experienced extensive degradation associated with Al depletion and porous oxide formation. Experimental observations reveal that corrosion resistance is governed by both the morphology and continuity of the oxide‐rich corrosion product scale and the chemical inertness of the X element toward chlorination. DFT calculations demonstrate that Cl adsorption strength, interlayer bond weakness, and preferential reactivity of Al, Hf, and B critically control atomic migration and lattice destabilization, while stronger M–X bonding contributes to improved structural stability during corrosion. These results establish a direct atomic‐to‐macroscopic correlation between MAX phase chemistry and molten chloride corrosion behavior, providing mechanistic design guidelines for corrosion‐resistant coatings in extreme environments.

MXene has attracted intense attention in optoelectronic photodetectors due to its outstanding electrical conductivity and tunable electronic properties. By using the Ti3C2Cl2 MXene irradiated with 100 keV N ions, a highperformance field-effect transistor (FET) photodetector was achieved and exhibited broadband photoresponse across the ultraviolet-visible-near infrared ray (UV-Vis-NIR) range. The responsivities of these FET photodetectors were as high as 5.3 & times; 104, 8.5 & times; 105, 3.3 & times; 104, and 2.8 & times; 105 A/W under 360, 550, 750, and 1060 nm light illumination, respectively, which are approximately two orders of magnitude higher than the other MXene-based photodetectors. The remarkable performance of the Ti3C2Cl2 FET photodetector is attributed to synergistic effect of band gap and photoconductive gain. Besides, the ion fluence has significant influence on the photoresponse of Ti3C2Cl2 FET photodetector, and there exists an optimized ion fluence to obtain the highest responsivity. These findings highlight a controllable strategy for introducing band gap in MXenes and pave the way for their application in next generation optoelectronic devices.

FeCrAlY coatings are promising protective materials for structural components in lead-cooled fast reactors, but their long-term performance in lead-bismuth eutectic (LBE) is often limited by insufficient oxide-scale stability and degradation of coating/substrate adhesion. In this work, a similar to 0.3 mu m AlOx-enriched surface layer was deposited on magnetron-sputtered FeCrAlY coatings on SIMP steel at 300 degrees C. The corrosion behavior, microstructural evolution, and adhesion stability were investigated by static LBE exposure at 500 degrees C for up to 2000 h, combined with SEM/EDS, XRD, TEM, and progressive-load scratch testing. The results show that the AlOx-enriched surface significantly improves the protective performance of the coating in high-temperature LBE. Compared with the FeCrAlY coating, the FeCrAlY/AlOx coating forms a multilayered oxide scale composed of alternating Fe-Cr-Al-O spinel-related oxide layers and Al-O-enriched transient oxide layers. The FeCrAlY/AlOx coating also exhibited markedly improved adhesion retention, maintaining approximately 94.8% and 53.2% of its initial adhesion value (Lc(1)) after 1000 h and 2000 h, respectively, whereas the FeCrAlY coating retained only approximately 21.2% and 18.3%. In contrast, the FeCrAlY coating develops a porous surface scale with limited barrier performance and exhibits pronounced Cr enrichment along the coating/substrate interface, which is accompanied by the 78.8% and 82.7% reductions of Lc(1) after 1000 h and 2000 h. The improved performance of the FeCrAlY/AlOx coating is attributed to the Al-enriched near-surface region, which promotes the timely formation of a protective scale and helps maintain interfacial stability during prolonged LBE exposure.

Ni-based coating (15Fe16Cr63Ni) was fabricated via laser cladding on one surface of a 316L stainless steel substrate, while the opposing surface was subjected to laser remelting. This configuration created a macrogalvanic couple, which is representative of some practical scenarios where dissimilar materials are connected. The corrosion behavior of this coupled system in NaCl-MgCl2-KCl salts at 700 degrees C was investigated up to 1200 h. The results highlight a galvanic effect, while the Ni-coating was cathodically protected. Despite this coupling, a continuous Fe-Ni-rich layer formed in-situ on the coating surface, acting as a barrier. A critical finding is that even under the protective influence of galvanic coupling, the corrosion products and mechanisms for both sides evolved similarly, forming Mg2SiO4 beneath the Fe-Ni layer. A dedicated short-term (100 h) test with isolated, symmetrically treated specimens confirmed that the intrinsic corrosion rate of the Ni-coating is lower than that of the laser-remelted surface. Thus, the findings stress the paramount importance of mitigating galvanic coupling in design. The behavior observed suggests that the Ni-coating has considerable potential; however, verifying its long-term durability through testing under fully electrochemically isolated conditions remains an essential prerequisite for its reliable application.

The performance of SiC fiber-reinforced SiC ceramic matrix composites (SiCf/SiC CMCs) is highly dependent on the interphases. Pyrolytic carbon (PyC) is a prevalent interphase, but its traditional chemical vapor deposition (CVD) method is complex and difficult to control. In this work, a facile CCl4 chemical etching strategy is proposed to directly fabricate uniform self-derived carbon interphases on SiC fibers, with thickness precisely tuned by varying the molar ratio of CCl4 to SiC fibers. SiCf/SiC CMCs reinforced by the etched fibers with a similar to 500 nm carbon interphase exhibit a flexural strength of 761 MPa, 3.77 times that of interphase-free composites. The composites show distinct pseudo-plastic fracture behavior with obvious fiber pull-out and interfacial debonding on the fracture surface, confirming that the etched carbon interphase enabled effective load transfer. This work provides a promising route for fabricating carbon interphases of high-performance SiCf/SiC CMCs.

This study presents a strategic paradigm combining photolithography-assisted electrodeposition with mechanically guided delamination for the fabrication of high-performance flexible Cu mesh transparent conductive electrodes. Through interfacial adhesion engineering, we construct a deliberately weakened yet precisely controllable Cu/ITO interface that enables clean, residue-free embedding of the metal mesh into elastomeric matrices by stress-assisted peeling. The electrodes deliver 81% optical transmittance and an ultralow sheet resistance of 0.1 Omega/sq, yielding a FoM of 15,969. XPS analysis indicates that separation proceeds via rupture of weak Cu-O-In and Cu-O-Sn coordination bonds, clarifying the chemical origin of the controllable delamination. The Cu mesh exhibits interfacial asymmetry, with a smooth Cu/ITO interface that minimizes contact resistance and a rough free-growth surface that promotes strong mechanical interlocking with the polymer, preserving structural fidelity under severe deformation. The embedded electrodes maintain Delta R/R0 < 0.25 at 50% strain and < 1.75 at 100% strain, and show rapid and durable electrothermal response. This scalable approach avoids chemical residues and mitigates transfer-induced damage, enabling stretchable transparent electrodes for wearable electronics and bio-integrated devices.

Radiation tolerance is a crucial parameter for MAX phases in nuclear structural applications. While metallic A-site nanolayers are traditionally regarded as the primary contributors due to their low MA-AM antisite defect formation energies, which facilitate defect accommodation and energy dissipation, recent advances in covalent MAX phases have opened new avenues for enhancing radiation damage mechanisms through X-site elements. In this work, we demonstrate that nonmetallic A-site and X-site elements play a decisive role in governing radiation response behavior. Unlike conventional metallic A-site MAX phases, which predominantly exhibit c-axis swelling under irradiation, the covalent variants Zr2SeC and Zr2SeP show anisotropic lattice expansion, characterized by a-axis-dominated distortion. This distinct behavior arises from strain redistribution mediated by variations in M-A-M bond angles, offering a mechanistic pathway to mitigate radiation-induced dimensional changes. Notably, these covalent MAX phases exhibit divergent structural evolution: Zr2SeC undergoes significant lattice swelling and partial amorphization, whereas Zr2SeP retains its hexagonal crystalline structure under identical irradiation conditions. We attribute this difference to the unique bonding configuration of Zr6X octahedra, where X’s electronegativity modulates Zr-Se bond cohesion and the energetics of ZrSe-SeZr antisite defects. The combined effects of reduced antisite defect formation energy and lowered vacancy migration barriers collectively confer exceptional intrinsic radiation tolerance to Zr2SeP grains. These findings provide a design framework for identifying radiation-resistant MAX phases with optimized structural stability for advanced nuclear applications.

Chromium-coated zircaloy is one of the most promising candidate materials to enhance the accident tolerance of nuclear fuel. By introducing a large number of yttrium oxide nanoparticles into the chromium coating (i.e., ODS-Cr coating), its thermal stability and radiation tolerance are remarkably improved. However, the effect of Y addition on its oxidation behavior needs to be urgently addressed. Here, the Xe-ions irradiated ODS-Cr coatings with different Y content were exposed to 1200 degrees C steam. Microstructural examinations show that, compared to pure Cr (which formed a similar to 2 mu m thick oxide scale), Y-doped coatings exhibited smaller size needle-shaped Cr2O3 blades and a substantially thinner oxide scale of 0.2-0.6 mu m, alongside fewer voids at the scale-coating interface. Additionally, the irradiation-induced cavities displayed much higher thermal stability. The improved oxidation resistance of ODS-Cr coatings indicates that the outward Cr diffusion at high temperatures was strictly suppressed by nano-oxides segregated at grain boundaries. These findings reveal the critical role of Y in tuning both the oxidation and radiation resistance of Cr-based protective coatings, providing valuable insights for the development of accident-tolerant fuel.

The molten chloride salt corrosion behavior of two heat-treated aluminum-containing austenitic (AFA) alloys, designated AFA1 (18Ni-14Cr-3Al) and AFA2 (25Ni-14Cr-3Al), was investigated at 700 degrees C in a NaCl-MgCl2-KCl (30.2-47.1-22.7 mol%) environment. A solution treatment of 1130 degrees C/1h followed by 700 degrees C/24 h aging was employed to precipitate secondary phases, including B2-NiAl, Laves, and NbC, which were characterized along with corrosion depth using scanning electron microscopy and energy-dispersive spectroscopy. The heat treatment significantly influenced the protective nature of the surface oxide scale. A less compact composite MgCr2O4 spinel was formed. Despite this, both heat-treated AFA alloys demonstrated superior long-term resistance, with corrosion depths of less than 100 mu m after 400 h. This performance markedly exceeds that of commercial 316 L stainless steel, which exhibited a corrosion depth of 260.1 mu m under the identical condition. The underlying corrosion mechanisms are discussed.

Sintered SiC coupons were irradiated by the 1.52-MeV protons at 65 + /-5 degrees C, and then were immersed in the deionized water at 345 degrees C and 15 MPa for evaluation of hydrothermal corrosion resistance. The proton irradiation produced a 20-mu m-thick and 0.45-dpa-damaged plateau, where the Si-C bonds were locally disordered, forming Si-Si and C-C homonuclear bonds and significantly improving the electrochemical activity, such as the potential difference and the ionization energy. The irradiated specimen loss its 0.56 % weight after the 2-days immersion, nearly an order of magnitude higher than that of the pristine specimen. It can be found that the proton irradiation greatly accelerated the hydrothermal corrosion of SiC, for the higher electrochemical activity promoted the dissolution reaction. Additionally, due to the disorder lattice, the transgranular corrosion mechanism, along with the intergranular corrosion, proceeded in the hydrothermal corrosion of irradiated SiC.

Solar salts have a high energy storage density, and using solar thermal power generation technology can provide humanity with long-term, stable, and low-cost electricity. However, severe corrosion of structural materials when in contact with molten chloride salts is one of the main challenges limiting their long-term service at high temperatures. In this study, two types of aluminium-containing austenitic (AFA) stainless steels: 18Ni and 25Ni AFA steels, were prepared and their corrosion behavior in molten chloride salt (NaCl-MgCl2-KCl with 30.2-47.1-22.7 mol.%) at 700 degrees C over different durations (200, 400, 600, and 800 h) was investigated. The corrosion products, thickness of the corrosion layer, and microstructure were characterized in detail. The effects of alloying elements on enhancing resistance to molten chloride salt corrosion were studied. Both types of AFA steels exhibited significant dissolution and oxidation behavior during the corrosion process, and the aggregation of Laves phases was observed. The corrosion depth after 800 h was found to reach a maximum of 131.3 mu m, significantly lower than conventional 304 stainless steels under similar conditions. Why AFA steels exhibit resistance to chloride salt corrosion is discussed. The findings provide valuable guidance for the development of structural materials suitable for high-temperature molten chloride salt applications.