CrFeNiMoAlx high-entropy alloy (HEA) coatings were deposited on Zr-1Nb substrates via magnetron co-sputtering for accident-tolerant fuel cladding applications. The Al content (x = 0-1) was controlled by adjusting the Al target power. The coatings exhibited dense, crack-free nanocrystalline microstructures and predominantly body-centered cubic (BCC) solid-solution phases, while increased Al content induced dual-BCC structures and minor intermetallic formation. Mechanical and corrosion properties strongly depended on Al concentration, with maximum hardness achieved at x = 0.7 due to optimized solid-solution strengthening and microstructural homogeneity. Electrochemical testing in 3.5 wt% NaCl solution revealed that the x = 0.7 coating exhibited the most stable passivation behavior and highest corrosion resistance. Under high-temperature, high-pressure pure water conditions (360 degrees C, 18.6 MPa, 360 h), all coatings maintained structural integrity and significantly reduced substrate oxidation. The improved corrosion resistance is attributed to the formation of a dense mixed oxide layer dominated by Cr2O3 and NiFe2O4, with Al contributing to oxide stability. These findings demonstrate that controlled Al addition is critical for optimizing the performance of HEA coatings, with CrFeNiMoAl0.7 identified as a promising candidate for advanced nuclear fuel cladding applications.

Incorporating alloying elements into aluminum nitride coatings is a well-established strategy for fabricating hard coatings with superior comprehensive properties, including high hardness, excellent wear resistance, outstanding thermal stability, and robust oxidation resistance. In this study, Ta was introduced to form a (Ti,Al,Ta)N solid solution with a fcc-structure. Compared to the Ti0.61Al0.39N coating with a hardness of 1822.5 HV, the Ta-doped coatings demonstrate markedly enhanced hardness values, reaching 2245.2 HV for TiAlTa0.02N, 2297.8 HV for TiAlTa0.05N, and 2317.3 HV for TiAlTa0.08N. This improvement can be attributed to lattice distortion and dislocation pile-up effects induced by alloying of Ta. Ta alloying reduced the wear rate compared with the TiAlN coating, although a slight trade-off was observed at higher Ta contents. Under the present 400 degrees C sliding condition, the wear rate decreased with increasing Ta content due to the improved hardness and the formation of oxide-rich tribofilms. The Ta element exhibits an age-hardening effect at 900 degrees C and effectively suppresses the transformation of h-AlN at 1100 degrees C, thereby ensuring that the coatings maintain structural integrity and superior high-temperature performance with hardness values exceeding 1500 HV. Additionally, the Ta element facilitates the direct formation of r-TiO2 and Al2O3, significantly hindering oxygen diffusion and enhancing oxidation resistance.

The CrAlN/(CrVTaTiW)Nx nano-multilayer coatings were fabricated by magnetron sputtering and subsequently heat-treated in a nitrogen atmosphere at 300°C, 500°C, 700°C, and 900°C for one hour. The phase identification, surface morphology, microstructure, and mechanical properties of the coating before and after heat-treatment were characterized using XRD, SEM, TEM, nanoindentation, radial cracking indentation, respectively. The results show that a stable FCC B1-NaCl superlattice with coherent interfaces and (111) texture still keep until up to 700 °C. However, oxide phases (Al2O3, CrO2) were detected after treatment at 300°C, 500°C and 900 °C. The sample with dCrAlN=4.5nm exhibited excellent thermal stability and mechanical properties, which can be attributed to its hybrid interface structure combining smooth and diffusion-type interfaces. Furthermore, the hardness increased from 21.6±1.9 GPa in the as-deposited state to 29.4±2.8 GPa after heat-treated temperature at 700°C, attributed to defect recovery. This enhancement is ascribed to defect recovery, stress relaxation, and interfacial strengthening. The coating also demonstrated improved fracture toughness compared to coatings with thicker bilayers. These results emphasize that careful control of layer thickness, interface structure and heat treatment process lead to enhanced hardness, toughness, and thermal stability in nano multilayer coatings.

High-entropy alloys are considered potential candidate materials for accident-tolerant nuclear fuel cladding because of their high-temperature stability and corrosion resistance. In this work, AlCrCuxFeNbNiy (x = 0.5, 1; y = 0, 0.3, 0.5, 0.7, 1.0) high-entropy alloys were designed to investigate the effects of Ni and Cu regulation on microstructure, mechanical properties, and corrosion behavior. The microstructure consists of tentatively presumed O-phase, FCC, and Al-contained intermetallic compounds. With increasing Ni content, the formation of AlNi is promoted. After texture correction, the diffraction intensity of FCC phase rises, while the diffraction signal related to Cu9Al4 diminishes. The hardness first declines and then rebounds to 695 HV at y = 0.5. Excessive Ni jeopardizes the hardness because the coarsening of dendritic Ni incorporation enhances the compressive strength but reduces their ductile strain. In the pure water corrosion environments at 360 °C and 18.6 MPa for 72 h, excessive Ni addition induces a net mass loss of the alloys, which is attributed to microstructure coarsening, aggravated chemical heterogeneity, and deteriorated stability of the oxide scale. Reducing Cu content can effectively mitigate Cu segregation in interdendritic regions and improve the overall microstructure homogeneity of the alloys. As a result, micro-galvanic corrosion is weakened, and a more continuous surface oxide layer can be formed during corrosion. AlCrCu0.5FeNbNi shows the best overall corrosion resistance, exhibiting only a slight mass gain of 2.58 mg/dm2 after high-temperature/high-pressure water corrosion. The coexistence of Al2O3 and CrNbO4 is likely favorable for the formation of a relatively compact oxide layer, which may hinder the inward transport of oxygen under high-temperature and high-pressure water environments. Cu/Ni regulation provides an effective strategy for balancing mechanical performance and corrosion resistance in AlCrCuxFeNbNiy alloys for ATF cladding applications.

CrAlN/(CrVTaTiW)Nx nano-multilayer coatings with varied CrAlN layer thicknesses were prepared by magnetron sputtering technology. These coatings were subsequently subjected to heat treatment at 300, 500, and 700°C in air atmosphere for one hour to observe their microstructure evolution, phase composition, and mechanical performance. All coatings retained a face-centered cubic (FCC) structure after heat treatment. After air heat treatment (300~500°C), all FCC (111) diffraction peaks shifted towards higher angles, accompanied by reduced peak broadening and variation of peak shape. Exposure to 700°C led to the emergence of oxide phases—notably Al₂O₃ and Cr₂O₃. Interestingly, the formation of V₂O₃ strongly depends on the CrAlN layer thickness and follows a complex, nonmonotonic "formationdisappearreformation" evolution pattern. Remarkably, a 300°C treatment leads to a pronounced increase in hardness. Among the series, the coating with a CrAlN layer thickness of 4.5 nm exhibits outstanding thermal stability and mechanical performance: its hardness rises impressively from 21.6 GPa (as-deposited) to 28.9 GPa after 500°C annealing. Transmission electron microscopy (TEM) revealed that local atomic ordering rearrangement and an increased dislocation density at interfaces are the primary mechanisms underpinning this remarkable hardening. These findings provide critical insights into designing thermally robust nano-multilayer coatings with superior mechanical performance.

High-voltage cables and accessories are the key components of power transmission, and the insulation interface is the weakest part of the insulation system. To study the effect of interface defects on the interface discharge characteristics of cables and accessories, first, the cross-linked polyethylene (XLPE), silicone rubber (SIR), and semiconductive (SEMI) samples are prepared, and the composite samples are fabricated (including XLPE/SIR and XLPE/SEMI composite samples). Second, the effects of interface defects on the breakdown, dielectric, and interface discharge properties of composite samples are analyzed. Finally, the composite interface defect model of cable and accessories is established to calculate the electric field distortion caused by the defect. The results show that the breakdown strength and interface discharge voltage of XLPE/SIR interface with voids and semiconductive defects are 36.7, 39.98 kV/mm and 12.07, 10.95 kV, respectively. The relative dielectric constant of the samples with defects increased significantly compared with the samples without defects. The breakdown strength of XLPE/SEMI interface with void, metal, and semiconductive defect is 65.00, 72.79, and 75.23 kV/mm, respectively, and the existence of defect leads to the overall increase in relative dielectric constant. The simulation results show that the maximum electric field distortion caused by voids and semiconductive defects in XLPE/SIR interface is 19.28 and 10.78 kV/mm, respectively, increasing by 155.70% and 42.97%. The maximum electric field distortion caused by voids, metal, and semiconductivity defects in the XLPE/SEMI interface is 19.09, 8.62, and 8.40 kV/mm, respectively, increasing by 186.21%, 29.24%, and 25.94%. The simulation results of electric field distortion are consistent with the breakdown test. This study is helpful to understand the effect of interface defects of cable accessories on electric field distribution, and it can provide reference for the operation, maintenance, and fault analysis of cable accessories.

The performance of Cu 2 ZnSnS 4 (CZTS) thin-film solar cells incorporating In x Ga 1− x N buffer layers were investigated using the SCAPS-1D simulation software. The analysis focused on the effects of absorber thickness and acceptor concentration ( N A ), buffer thickness and donor concentration ( N D ), and defect density on key photovoltaic parameters, including short-circuit current density ( J sc ), open-circuit voltage ( V oc ), fill factor (FF), and power conversion efficiency (PCE). Simulation results reveal that incorporating indium (In) into GaN improves energy band alignment with CZTS layer and enhances carrier transport characteristics. At an In composition of x = 0.16, the buffer layer forms a favorable spike-type conduction band offset of approximately 0.10 eV with CZTS, which reduces interfacial recombination and facilitates efficient carrier extraction. With normalize performance conditions, the device achieves a peak PCE of 25.88%, accompanied by J sc of 28.43 mA cm −2 , V oc of 1.08 V, and FF of 84.29%. Interfacial defect simulations for CZTS/In 0.16 Ga 0.84 N interface further indicate that keeping the trap density below the low 1 × 10 12 cm −2 range is essential for achieving high V oc and FF. Furthermore, The In 0.16 Ga 0.84 N buffer layer also exhibits stable performance across a wide defect concentration range (up to 10 18 cm −3 ) and an operating temperature range of 200–400 K. These findings provide valuable insights into the compositional and interfacial design of high-efficiency, Cd-free CZTS photovoltaic devices.

In this work, by modulating the stacking period of the individual GeTe and Sb2Te3 layers, a balance between electrical conductivity and Seebeck coefficient can be achieved to maximize the thermoelectric efficiency through the synergistic effect of material design flexibility and interface engineering. The coupling of acoustic and optical branches in the phonon dispersion of Sb2Te3, along with the presence of multi-carrier pockets in the band structure of GeTe, offers theoretical support for constructing a multilayer structure. The multilayer films sustain the two-phase structure composed of Sb2Te3 and GeTe phases. As the period number increases, there is an increase in optical band gap and carrier concentration, and a decrease in resistivity. The layered interface and nanocrystalline boundary inside the multilayer films are important scattering sources and significantly reduce the carrier mobility. In addition, nano-multilayer films modulate the carrier concentration to maintain an optimal order of 10(19)similar to 10(20) cm(-3). The maximum power factor of GeTe/Sb2Te3 multilayer films obtained is 1081 mu W/mK(2) at 473 K for single-period film. The power factor unexpectedly decreases as the number of periods in the film increases, which could be attributed to the enhanced thickness leading to higher carrier concentration and reduced nano scale effect.

The investigation of high entropy alloy (HEA) coatings as a promising material for application in nuclear fuel cladding has been motivated due to their exceptional mechanical and functional properties. This study aims to fabricate AlCrCuFeMoNix (x=0.5, 1.2, 1.8 and 2.3) HEA coatings to enhance the accident tolerance of nuclear fuel cladding through magnetron sputtering on zirconium alloy substrates. The mechanical properties of the coatings, as well as their resistance to high temperature steam oxidation and high-pressure pure water corrosion, were investigated. It was found that the coating with x = 0.5 exhibited optimal hardness and Young's modulus of 8.57 GPa and 170.75 GPa respectively. After subjecting the coated samples to high-temperature and high-pressure pure water corrosion for 3 days, it was observed that aluminum within the coating formed dense spinel NiAl2O4 which effectively inhibits oxygen diffusion, thereby enhancing the corrosion resistance of the coatings. In terms of accident-tolerance performance in reactor environments at temperatures above 1200 degrees C, it was found that when x = 1.8, dense Al2O3 and oxide featuring a spinel structure generated on the coating surface which significantly reduced the diffusion rate of oxygen ions during high-temperature steam oxidation. The oxidative weight gain of the coated samples was decreased by 70.41 % compared to the uncoated zirconium alloy, demonstrating excellent accident tolerance properties.

The performance of Cu2ZnSnS4 (CZTS) thin-film solar cells incorporating InxGa1-xN buffer layers were investigated using the SCAPS-1D simulation software. The analysis focused on the effects of absorber thickness and acceptor concentration (N-A), buffer thickness and donor concentration (N-D), and defect density on key photovoltaic parameters, including short-circuit current density (J(sc)), open-circuit voltage (V-oc), fill factor (FF), and power conversion efficiency (PCE). Simulation results reveal that incorporating indium (In) into GaN improves energy band alignment with CZTS layer and enhances carrier transport characteristics. At an In composition of x = 0.16, the buffer layer forms a favorable spike-type conduction band offset of approximately 0.10 eV with CZTS, which reduces interfacial recombination and facilitates efficient carrier extraction. With normalize performance conditions, the device achieves a peak PCE of 25.88%, accompanied by J(sc) of 28.43 mA cm(-2), V-oc of 1.08 V, and FF of 84.29%. Interfacial defect simulations for CZTS/In0.16Ga0.84N interface further indicate that keeping the trap density below the low 1 x 10(12) cm(-2) range is essential for achieving high V-oc and FF. Furthermore, The In0.16Ga0.84N buffer layer also exhibits stable performance across a wide defect concentration range (up to 10(18) cm(-3)) and an operating temperature range of 200-400 K. These findings provide valuable insights into the compositional and interfacial design of high-efficiency, Cd-free CZTS photovoltaic devices.

Mg‐doped Cu 2 ZnSnS 4 films were prepared by sol–gel method with varying Mg concentration. The effects of Mg concentration on the phase structure, optical properties, and electrical properties were investigated. The incorporation of Mg did not alter the phase structure but caused a shift of diffraction peaks to larger angles and a slight reduction in the bandgap as the Mg concentration increased. Sample S3‐4% exhibited higher lattice strain, whereas sample S4‐6% presented the lowest lattice strain value of 0.63. XPS results demonstrate that the chemical valence states of the Cu, Zn, Sn, and S elements remained unchanged in the Cu 2 Mg x Zn (1‐x) SnS 4 compounds. Additionally, the incorporation of Mg into Cu 2 ZnSnS 4 induced slight negative shifts in binding energies and decreased the energy difference between the valence band and the Fermi level, while also enhancing crystallization, resulting in more uniform and compact structure. Furthermore, sample S2‐2% exhibited a significant enhancement of absorption value and electrical properties.

A novel TiN/(CrVTaTiW)Nx multilayer coating, consisting of the high-entropy alloy nitride and the binary nitride was prepared by DC magnetron sputtering. Detailed investigation about the microstructure and mechanical attributes of the multilayer films was conducted, with particular emphasis on the influence of high entropy nitride (HEN) modulation layer's thickness. The results reveal that all samples exhibited a face-centred cubic (fcc) crystal structure with a (111) preferred orientation. Notably, the hardness and elastic modulus of multilayer films increase with increase of the HEN layer's thickness. When the thickness of the HEN layer reached 4.8 nm, the hardness and elastic modulus of the TiN/(CrVTaTiW)Nx multilayer reached the maximum values of 25.33 GPa and 311.95 GPa, respectively. These results indicate the key role of the HEN layer as a modulation layer within the coating, ultimately demonstrating the importance of thickness on the structure and properties of TiN/ (CrVTaTiW)Nx nanomultilayer films.

A series of TiN/(CrVTaTiW)Nx multilayer coatings, with TiN and (CrVTaTiW)Nx serving as crystallization template layers, were fabricated by magnetron sputtering technology. The growth behavior, interface structure, and mechanical properties were detailed investigated. The results reveal that the samples possessed a facecentred cubic phase structure with a NaCl-type crystal structue with a (CrVTaTiW)Nx solid solution phase on one sub-lattice. Distinct periodic modulated structure and columnar crystal growth were observed. The (CrVTaTiW)Nx layer, acting as a crystallization template, plays a pivotal role in the performance and optimization of the multilayer configuration. The results indicate that by precise manipulation of the growth process, the multilayer coatings exhibited a uniform and compact periodic structure, resulting in a notable enhancement in hardness. Furthermore, the thermal stability and thermal hardness properties of the coatings were assessed under varied annealing temperatures. Notably, for the samples employing TiN as the crystallization template layer and annealed at 300 degrees C, the hardness increased from 25 to 29 Gpa, meanwhile these samples exhibited a superior crystallization characteristics, higher hardness and exceptional crack resistance.

High entropy alloy AlCrCuFeMoNbx (x=0.5, 0.8, 1.4, 2.0) coatings were deposited on Zr-1Nb alloy substrates by magnetron co-sputtering to improve the accident tolerance capability of the nuclear fuel cladding. The structural and accidental tolerant properties of high-entropy alloy coatings have been investigated comprehensively. The results show that coatings with varying Nb contents exhibit amorphous structures. The hardness and elastic modulus of the coatings increase with the Nb content, reaching their maximum values at x = 2.0, which are 11.38 GPa and 186.05 GPa, respectively. In both the simulated normal operating and accident environment of the nuclear fuel cladding, the oxidation resistance of the coating has been investigated. The best oxidation resistance was achieved at x=0.8 in pure water at 360 degrees Cunder 18.6 MPa for 3 days. The dense Cr2O3 and CrNbO4 oxide films generated on the surface hinder the diffusion of oxygen ions, and account for the lower weight gain 5.10 mg/dm2, decreased by 56.4 % compared to that of the uncoated zirconium alloy. The coating with x=0.5 showed a drastic reduction in oxidized weight gain by 84.02 % compared to the uncoated zirconium alloy in water steam at 1200 degrees C, demonstrating excellent accident tolerance, which is due to the dense alpha-Al2O3 and CrNbO4 protective layer generated on the surface of the coating. These findings suggest that high entropy alloy coatings have promising accidental tolerance capabilities for nuclear fuel cladding.

Mg-doped Cu2ZnSnS4 films were prepared by sol-gel method with varying Mg concentration. The effects of Mg concentration on the phase structure, optical properties, and electrical properties were investigated. The incorporation of Mg did not alter the phase structure but caused a shift of diffraction peaks to larger angles and a slight reduction in the bandgap as the Mg concentration increased. Sample S3-4% exhibited higher lattice strain, whereas sample S4-6% presented the lowest lattice strain value of 0.63. XPS results demonstrate that the chemical valence states of the Cu, Zn, Sn, and S elements remained unchanged in the Cu2MgxZn(1-x)SnS4 compounds. Additionally, the incorporation of Mg into Cu2ZnSnS4 induced slight negative shifts in binding energies and decreased the energy difference between the valence band and the Fermi level, while also enhancing crystallization, resulting in more uniform and compact structure. Furthermore, sample S2-2% exhibited a significant enhancement of absorption value and electrical properties.

Zintl compounds Mg3Bi2 are promising thermoelectric materials due to their intrinsic "electron-crystal, phonon-glass" nature and low cost. However, the pristine bulk Mg3Bi2 exhibits semimetallic characteristics with a low band gap, consequently leading to suboptimal thermoelectric performance. In this work, low-dimensional engineering has been conducted, and the electronic structure and thermoelectric properties of both bulk and monolayer Mg3Bi2 were systematically assessed using First-principles calculation, Boltzmann transport theory and relaxation time approximation. The findings indicate that N-type Mg3Bi2 has a higher Seebeck coefficient compared to P-type for both bulk and monolayer, attributed to the multi-valley structure of the conducting band. The energy band degeneracy of CBM increases for the two-dimensional structure, and the lattice thermal conductivity is significantly reduced by the higher lattice anharmonicity and lower phonon group velocity, which greatly improves the thermoelectric properties of Mg3Bi2. The thermoelectric performance of N-type Mg3Bi2 is superior to that of P-type, and it is particularly prominent in monolayer systems. The largest ZT values of N-type monolayer Mg3Bi2 is up to 3.15 obtained at T = 900 K and n = 8.8 x 1011 cm-2. The results show that the low dimensional process can effectively improve the ZT value and conversion efficiency of thermoelectric materials.

Cross-linked polyethylene (XLPE) cables play an important role in power systems to transport electrical energy, and moisture is one of the important predisposing factors for insulation failure in medium and high-voltage cables. In this paper, a temperature-moisture accelerated ageing experiment is designed, and a method for assessing the moisture status of cable insulation is proposed. This is achieved by analysing the frequency-domain dielectric-spectral curves of samples exposed to different levels of moisture and calculating the integral value of the tangent angle of the low-frequency (0.1-1 Hz) dielectric loss as the characteristic parameter. Firstly, according to the principle of time-temperature superposition, the reduced relationship model between ageing time and ageing temperature is established. Secondly, the experimental data are analysed by nonlinear regression method, and the intrinsic relationship between ageing time, temperature, moisture content and ageing characteristic quantity is established, respectively. Based on the above results, the temperature-moisture coupling coefficient is further revised, and the equation of the ageing status of XLPE insulated cables under the two-factor coupling of temperature-dampness is established. Lastly, the accuracy of the model is verified by using laboratory ageing samples and returned cables. The results indicate that the model achieves an accuracy of 95.49% under controlled laboratory conditions. Then the service life of the returned cable is quantitatively analysed, and the calculated results are within the range of the model. This work has important guiding significance for the assessment of ageing status of power cables.

The combined insulation interface of a high-voltage cable and accessories is the weakest part of a cable system. In this paper, the parameters of the dielectric constant, thermal conductivity, and elastic modulus of cross-linked polyethylene (XLPE) and silicone rubber (SIR) are obtained experimentally. On this basis, the model of a specific type of 110 kV cable and prefabricated insulation joint is established. A simulation of the electric–thermal–stress coupling field in the presence of typical defects in the main insulation–inner semi-conductive (SEMI) shielding layer (XLPE/SEMI interface) and the main insulation–silicone rubber insulation layer (XLPE/SIR interface) is studied. The simulation results show that at the XLPE/SIR interface, the electric field distortion caused by bubble defects reached 20.17 kV/mm, and the temperature rose to 56.15 °C. The effect of air-gap defects on the interface is similar to that of bubble defects. In addition, the semi-conductive impurity defects induced an increase in temperature to 56.82 °C and an increase in stress to 0.32 MPa. At the XLPE/SEMI interface, the electric field distortion induced by bubble defects was 19.98 kV/mm, and the temperature rose to 61.72 °C. The electric field distortion caused by metallic and semi-conductive defects was 8.44 kV/mm and 8.64 kV/mm, respectively. This study serves as a reference for the fault analysis and the operation and maintenance of cable accessories.

The high carrier concentration and low Seebeck coefficient limit the thermoelectric properties of Ge2Sb2Te5 materials. In this paper, Bi-doped Ge2Sb2Te5 thin films with different doping amounts were prepared by magnetron sputtering. The thermoelectric properties of Bi-doped Ge2Sb2Te5 were measured by experiments and predicted by density functional theory and Boltzmann transport theory. The results show that Bi atoms occupy Ge vacancies and bond with Te atoms. The replacement of Ge2+ vacancy with Bi3+ effectively modulates the carrier concentration and improves the Seebeck coefficient. Bi doping increases the degeneracy of the valence band and density of state near the valence band maximum (VBM), and thereby beneficial for the thermoelectric properties of p-type Ge2Sb2Te5, while not desirable for n-type. At 673K, the power factor of the sample at 20W doping power reaches 549.56 μWK-2m-1, which is nearly fifteen times that of the intrinsic Ge2Sb2Te5.