The inherent brittleness greatly limits the wide application of high performance ceramic materials in the industrial field. In this paper, ultrahigh toughness 3YSZ ceramics were prepared by electric field assisted dynamic hot forging. The microstructure evolution and mechanical properties of 3YSZ ceramics under the coupling of electric field and dynamic force field were studied. The results show that: under the conditions hot forging for 10 min at a constant furnace temperature of 1 000 ℃, electric field strength of 20 V/cm, current density of 140 mA/mm², and dynamic pressure of (50±10) MPa, the Vickers hardness and fracture toughness of 3YSZ ceramic reache (12.40±0.58) GPa and (10.69±0.33) MPa·m^1/2, respectively, which increase 11.5% and 54.9% compared with the conventional sintered ceramic. The remarkable improvement of toughness mainly due to the stability of the tetragonal phase in 3YSZ ceramics reduced by electric field assisted dynamic hot forging, which makes it easier to undergo phase transformation when induced by external force, so as to effectively inhibit crack propagation. Electric field assisted dynamic hot forging technology has the advantages of no need to add reinforcement phase and remarkable toughening effect, which provides a new path for toughening high performance 3YSZ ceramic materials.

Si₃N₄ ceramics exhibit excellent mechanical properties due to their strong covalent bonding characteristics, however, this characteristic makes them difficult to secondary process, severely limiting their widespread industrial applications. In this study, dynamic hot forging (DHF) technology was employed to process commercial Si₃N₄ ceramics, the effects of hot forging temperature on the microstructure and mechanical properties of materials were studied. The results indicate that under a dynamic pressure of (60±5) MPa and a hot forging temperature of 1 800 ℃, the Si₃N₄ ceramics exhibit optimal mechanical properties, with a hardness of 13.84 GPa, a fracture toughness of 6.88 MPa·m^1/2, and a bending strength reaching 925 MPa. All performance metrics significantly surpassing those of the original samples. This performance enhancement is primarily attributed to two key factors: firstly, the elimination of defects such as pores during the hot forging process, and secondly, the structural texturing effect induced by dynamic pressure. The DHF technology developed in this study provides an effective new method for the secondary processing and strengthening of high-performance difficult-to-machine ceramic materials.

Corrosion is common in metal materials, which limits the comprehensive utilization of metal resources. In recent years, inspired by the super-wetting phenomenon in nature, superhydrophobic coating, as a new metal protection mean, has been widely used. In this paper, the basic theory of superhydrophobic surface is expounded, and the recent development of superhydrophobic coatings on magnesium alloy, aluminum alloy, carbon steel, and titanium alloy is emphatically summarized, in order to provide reference and guidance for developing new functional materials, promoting related technological progress, and promoting cross-application in many fields.

In the harsh service environment, spacecraft must withstand long-term exposure to aerobic environments, extreme aerodynamic heating, high temperatures, and high pressures. Thermal protection materials show excellent thermal insulation, protection, compression resistance, and impact resistance under the dual action of high temperature and strong airflow, and can maintain stable chemical and physical characteristics. As an anti-thermal insulation materials, its low thermal conductivity can significantly reduce heat transfer while retaining the necessary mechanical properties, which has important application value in the aerospace field, and can ensure the stable operation of internal equipment in high temperature environment. This paper systematically discusses the basic principles and key properties of two typical anti-thermal insulation materials (ceramic thermal protection materials and metal thermal protection materials), analyzes their preparation technology and practical applications, summarizes the existing main problems, and puts forward the future development direction, providing a new perspective and reference for the research in this field.

In order to reduce the thermal expansion coefficient of SiC-based composites, this paper composited positive thermal expansion material SiC and negative thermal expansion material β-eucryptite to prepare a near-zero expansion SiC-based composite, and systematically studied the effects of β-eucryptite content on the porosity, microstructure, thermal and mechanical properties of the material. The results show that with the increase of β-eucryptite content, the porosity of the material decreases, the closed porosity increases, and the pores gradually change from irregular shape to spherical shape. Under the dual effect of porosity and β-eucryptite phase, the coefficient of thermal expansion of the material decreases. When the mass fraction of β-eucryptite increases from 20% to 50%, the average coefficient of thermal expansion of the material at 30-1 200 ℃ decreases from 2.30×10^-6 K^-1 to -0.80×10^-6 K^-1, the porosity decreases from 36.9% to 12.9%, the thermal conductivity increases from 6.31 W/(m·K) to 8.85 W/(m·K), and the compressive strength increases from 176.3 MPa to 375.6 MPa.

Electrocatalytic nitrogen reduction reaction (eNRR) is considered as an effective strategy for producing $NH_{3}/NH_{4}^{+}$ with low concentrations under environmental conditions, and designing appropriate catalysts is the key to efficiently driving eNRR. This study used a hydrothermal method to prepare MIL-101 catalyst and investigated the effects of hydrothermal temperature and Gd element doping on the eNRR performance of MIL-101 catalyst. The results show that 150-M-101 has the highest crystallinity and eNRR performance (NH₃ yield of 11.5 μg/(h·mg), Faraday efficiency of 30.5%). The surface of MIL-101-0.5Gd is concave, exposing the internal rough pore structure, improving the apparent activity of the catalyst. At the same time, the increase of oxygen vacancy concentration optimizes the characteristic activity of the catalyst, the NH₃ yield and Faraday efficiency at 0.1 mol/L LiClO₄ electrolyte and -1.3 V potential are 16.7 μg/(h·mg) and 37.6%, respectively, which are better than undoped 150-MIL-101. The catalyst also has good long-term stability.

High resistivity inorganic oxide nanoparticles are widely used as insulation materials for soft magnetic powder cores to reduce the eddy current loss at high frequency, as well as enhance the operational stability and energy utilization efficiency of the devices. In this research, the warm pressing process was introduced into the preparation of FeSiBC amorphous magnetic powder cores aiming at the problem that the presence of nonmagnetic oxide nanoparticles leads to a decrease in the densification and permeability of powder cores. It focused on the effects of warm pressing temperature on the formability, magnetic properties, and mechanical properties of FeSiBC amorphous magnetic powder cores. The results demonstrate that the softened resin can effectively fill the gap between the magnetic powders and enhance the bonding effect at a warm pressing temperature of 120 ℃, so that the powder core has the best compression performance and comprehensive magnetic properties. In this condition, the compressive strengths are 220.0 MPa and 269.1 MPa for the raw and coated powder cores, respectively, which are 107.5% and 47.8% higher compared to room temperature pressing powder core; the effective permeability stabilize to 20.8 H/m and 18.7 H/m in the range of 100 kHz-10 MHz, respectively, which are 20.9% and 16.9% higher compared to room temperature pressing powder core; the alternating current losses are 2 693.5 kW/m³ and 2 228.0 kW/m³ at 1 MHz and 0.05 T, respectively, which are 13.9% and 21.3% lower compared to room temperature pressing powder core. In this work, the optimized parameters in the warm pressing process are explored to enhancing the application frequency and energy utilization efficiency of magnetic powder cores, which provides insights for the preparation of FeSiBC magnetic powder cores with excellent performance.

Applying certain constraint and pre-stress to the ceramics can change the damage response of the ceramics to the impact and delay the interface defeat, thus improving the penetration resistance of the composite armor. This paper introduced the ballistic mechanism of ceramic composite armor and reviewed the effects of common confined patterns (axial constrained, radial constrained, and three-dimensional constrained) on its ballistic performance, with a view to providing certain reference for the structural design, ballistic mechanism research, and application expansion of ceramic composite armor.

In this paper, combined with surface etching and in-situ oxidation process, X-ray diffractometer, scanning electron microscope, energy spectrometer, X-ray photoelectron spectrometer, fiber optic spectrometer, and Fourier transform infrared spectrometer were used, the variations in the oxidation products on the surface of Fe-Mn-Al-Ni-C lightweight steel and their effects on photothermal conversion performance were studied by adjusting the oxidation temperature. The results show that applying etching pretreatment promotes the generation of nano-lamellar oxides, thereby effectively improving the photothermal conversion performance of the alloys compared to using the in situ oxidation process alone. After etching, the oxide size increases as the oxidation temperature rises from 300 ℃ to 400 ℃, leading to an improvement in the photothermal conversion performance of the alloy; the solar energy absorptance and photothermal conversion efficiency of the alloy reach peaks of 96.1% and 90.2%, respectively, after oxidation at 400 ℃ for 2 h; when the oxidation temperature increases to 500 ℃, increased thermal stress due to the mismatch of thermal expansion coefficients causes slight detachment of the oxide layer from the alloy surface, resulting in a decline in photothermal performance; oxidation at 600 ℃ leads to severe oxide layer detachment and the formation of Al2O3, further reducing the photothermal performance.

Three dimensional foam SiC based titanium suboxide (SiC/Ti_nO_2n-1) electrode was prepared by sol-gel sintering method. The surface morphology, phase composition, and electrochemical property of titanium suboxide electrodes were characterized by scanning electron microscopy, X-ray diffraction, and electrochemical workstation. The degradation effect of organic pollutants was tested using a ultraviolet-visible spectrophotometer. The results show that the coating of foam SiC based titanium suboxide electrode prepared at 1 050 ℃/2 h sintering condition has good quality, continuous and uniform distribution, and the content of conductive phase Ti₄O₇ is the highest (mass fraction is 37.5%), the film charge transfer resistance is the lowest (16.75 Ω). It shows a faster degradation rate (reaction rate constant is 0.60 h^-1) and lower energy consumption (11.63 (kW∙h)/m³) for simulated pollutant acid orange G. Both •OH and $ \mathrm{SO}_{4}^{.-}$ are involved in the degradation of acid orange G, and their contributions to the removal of acid orange G are almost the same. The presence of inorganic ions $ \mathrm{HCO}_{3}^{-}$, $ \mathrm{NO}_{3}^{-}$, $ \mathrm{H}_{2} \mathrm{PO}_{4}^{-}$ has an inhibitory effect on the degradation of acid orange G, while Cl^- promotes the degradation. The electrode exhibits high stability in multiple degradations.

Rare earth hafnates exhibit low thermal conductivity, high melting point, excellent high-temperature phase stability, and robust environmental corrosion resistance, offering promising applications in thermal/environmental barrier coatings for new-generation aero-engine hot-end parts. This paper focuses on the elaboration of rare earth hafnate materials as environmental barrier coatings, summarises the research progress in water vapor, molten CaO-MgO-Al₂O₃-SiO₂, molten salt, and coupled environment of water vapor and molten CaO-MgO-Al₂O₃-SiO₂ corrosion resistance, and outlines its future development direction.

Dual-ion doping is an effective method to improve the electrochemical properties and cycle stability of Li₂MnO₃, a lithium-rich manganese-based cathode material. However, the influencing mechanism of the subtle interaction between doped ions on the performance of Li₂MnO₃ is still unclear. This study investigated the lattice structure, electronic structure, O stability, and Li diffusion dynamics of Mg single doped and Mg/Al co-doped Li₂MnO₃ through first-principles calculation. The results show that compared with Mg single doping case, Mg/Al co-doping can cause significant lattice distortion, enhance the electrochemical activity of local O, but also sacrifice some O stability, and promote the intralayer diffusion of local Li. This study highlights the differences in the effects of Mg/Al co-doping and Mg single doping on the electrochemical properties of Li₂MnO₃, providing a theoretical basis for optimizing the design of lithium-rich manganese-based cathode materials.

Numerical simulation analysis was conducted on the hot isostatic pressing of titanium alloy powder to form impeller discs. The distribution of equivalent plastic strain and the variation of node density over time, as well as the distribution of relative density of pressed parts were studied, and impeller disc samples were prepared using hot isostatic pressing technology. The results show that the numerical simulation results show good consistency with the experimental data. This discovery fully demonstrates the effectiveness of numerical simulation technology in the hot isostatic pressing process of impeller discs, and the accuracy of predicting the forming characteristics. This not only provides strong data support for optimizing the production process of impeller discs, but also lays a solid foundation for the subsequent prediction of complex parts.

To overcome the drawbacks of high density and single-mode magnetic loss in magnetic metals, Co-based metal organic frameworks were prepared by precipitation method using Co salt and trimesic acid as raw material and organic ligand, respectively. Magnetic metal Co/C composite microwave absorber powders were synthesized through calcination, and the effects of calcination temperature on the morphology and microwave absorption properties of Co/C microwave absorbers were studied. The results show that calcination temperature significantly affect the morphology and properties of Co/C absorbers, uniformly dispersed particle structure and porous framework structures can be obtained after calcination at 500 ℃ and 600 ℃, respectively, while chain-like rod structures can be obtained at 700 ℃ and 800 ℃. The sample calcined at 800 ℃ exhibits the best electromagnetic wave absorption property, with a maximum reflection loss of -35 dB and an effective absorption bandwidth of 0.56 GHz at 13.76 GHz when the tested sample thickness is 4.5 mm. The improvement in microwave absorption property is attributed to multiple loss mechanisms (such as eddy current and exchange resonance), suitable electromagnetic parameters and attenuation constant, and the synergistic effect between the porous structure and various components.

Continuous carbon fiber reinforced ZrB₂-SiC composites have attracted much attention in the field of thermal protective structural materials for space vehicles due to their excellent oxidation and ablation resistance. In this paper, 2D C_f-ZrB₂-SiC composites were prepared by the slurry brushing-hot pressing method, the feasibility of using micron-sized powder slurry to prepare 2D C_f-ZrB₂-SiC composites was explored, the effects of sintering temperatures on the microstructure and mechanical properties of the materials were investigated, and the ablation resistance of the materials was tested. The results show that the 2D C_f-ZrB₂-SiC composite prepared by micron-sized powder slurry brushing-hot pressing method has the highest density and flexural strength after sintering at 2 000 ℃, with an open porosity of 8.01% and a flexural strength of 191.3 MPa; it appears good ablation resistance, the surface response temperature reaches 2 600 ℃, and the linear ablation rate is 3.51 μm/s after plasma flame ablation for 300 s.

SiC coating was prepared on high-purity graphite using chemical vapor deposition method, and hydrothermal corrosion experiment was conducted to study the relationship between chemical vapor deposition process, coating morphology and structure, and coating hydrothermal corrosion behavior. The results show that with the increase of dilution hydrogen flow rate, the average grain size of the coating decreases, the possibility of free Si appearing in the coating increases, and the resistance to hydrothemal corrosion gradually decreases. As the deposition temperature increases from 1 000 ℃ to 1 300 ℃, the crystallinity and average grain size of the coating first increases and then decreases. The maximum value is obtained at a deposition temperature of 1 200 ℃, and the coating structure and grain morphology remain intact after hydrothermal corrosion. As the temperature of the methyltrichlorosilane water bath increases, the average grain size of the coating increases. The coating prepared at a water bath temperature of 50 ℃ has the worst crystallinity and is the most severely corroded.

A theoretical prediction model for geometry dimensions of single-layer single-track coatings was established by analyzing the interactions between metal particles, substrate, and laser beam during the laser cladding process. Based on the experimental results of laser cladding Ni60 alloy coating on the surface of 316L stainless steel, the regression equations between the correction coefficients and the process parameters were achieved by multiple regression analysis. Therefore, the modified prediction model of geometric dimensions of single-layer single-track coatings was obtained by introducing the correction coefficients into the theoretical prediction model. The validation experiment was carried out under the conditions of the laser power, the scanning speed, and the powder feed rate of 1 750 W, 3.5 mm/s, and 0.099 g/s, respectively. The results show that the average relative errors between the modified prediction and experimental values of melt width, melt height, and melt depth are 0.85%, 2.47%, and 6.05%, respectively. The prediction accuracy of the modified prediction model is significantly improved compared with that of the theoretical prediction model. The results of the validation experiments show the feasibility of the modified prediction model. The Ni60 alloy coating is rich in hard phases, and its microhardness can be up to 3.4 times of that of 316L stainless steel substrate, and its wear rate is about 50% of that of substrate. The strengthening effect is remarkable.

In order to improve the ablation resistance of C/C-SiC composites, ZrC nano-powder modified C/C-SiC composites were prepared by the reactive melt infiltration (RMI) with ZrC nano-powder and Si powder as raw materials. X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometer were used to investigate the effects of ZrC nano-powder contents on the microstructure and ablation properties of C/C-SiC composites. The results indicate that with the increase of ZrC nano-powder content, the porosity of the composite increases, but the density changes little. Meanwhile, part of ZrC nano-powders are diffusely distributed in the SiC matrix, and part of them are agglomerated. After ablation for 30 s, when the mole fraction of ZrC nano-powder is 6%, the composite exhibits the lowest mass and linear ablation rates of 2.0 mg/s and 3.9 μm/s, respectively. And with the increase of ZrC nano-powder content, the content of ZrO₂ formed during ablation increases, this leads to a notable enhancement in the pinning effect on SiO₂, effectively improving the ablation resistance of C/C-SiC composites.

As an alternative technology for electroplating and thermal spraying, extreme high-speed laser cladding technology has attracted more and more attention since its inception. The technical principle of extreme high-speed laser cladding was clarified by comparing with conventional laser cladding. The technical characteristics and advantages were analyzed by comparing with electroplating, thermal spraying, and conventional laser cladding. This work reviewed the current research status of extreme high-speed laser cladding, including equipment, material, process, microstructure, and application, etc., analyzed the shortcomings of this technology, and offered suggestions for the research and application development.

Simplifying the preparation process of CuSnTi solder and reducing production costs are crucial for the development of high-performance tools. In this paper, direct mechanical mixing technique of Cu, Sn, and Ti metal powders was employed to synthesize CuSnTi brazing materials, which was then used to brazed PcBN/YG8 heterogeneous materials. The evolution of microstructures of CuSnTi brazing materials at different reaction temperatures were studied, the in-situ reaction mechanism of brazing materials during the brazing process was revealed, and the microstructure and properties of joint were analyzed. The results show that the in-situ reaction of CuSnTi brazing material can be mainly divided into three stages: in the first stage, Sn melts and reacts with Cu to form Cu₆Sn₅ and Cu₃Sn in sequence; in the second stage, CuTi, Cu₄Ti₃, CuTi₃, and CuSn₃Ti₅ precipitate surrounding Ti particles in sequence; in the third stage, liquid brazing material reacts with graphite substrate leading to the formation of TiC, and then solidification and precipitation of irregular CuSn₃Ti₅. PcBN/YG8 joints brazed with mechanical mixed powder brazing material and alloy powder brazing material both have good metallurgical bonding, with shear strengths of 96.06 MPa and 91.40 MPa, respectively. The joint brazed with mechanical mixed powder brazing material breaks at the PcBN site and exhibits excellent mechanical properties.