A high-temperature-resistant and high-performance hafnium oxide (HfO₂) coating for aerospace engines was developed. HfO₂ thin film coatings were prepared by chemical vapor deposition (CVD) at 1200, 1250, 1300, and 1350 °C, respectively. The crystal structure and surface morphology of the HfO₂ thin films at different deposition temperatures were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The effect of deposition temperature on the mechanical properties of the HfO₂ thin films was studied by means of the drainage method and nanoindentation. The results showed that the HfO₂ coatings deposited at different deposition temperatures are monoclinic crystal structures, and the surface morphology changes from cellular particles to columnar particles, and finally, to a loose and porous layered structure. When the deposition temperature is 1300 °C, the density of the HfO₂ film is the highest, 9.62 ± 0.03 g/cm³, and the hardness is the highest, 7.33 ± 0.04 GPa. A HfO₂ coating with the best comprehensive mechanical properties was prepared by changing the deposition temperature, which provided an experimental basis for the application of a HfO₂ coating in the aerospace field.

This study investigates the deposition of tantalum (Ta) coatings on carbon foams using the chemical vapor deposition (CVD) method to enhance their compressive strength. Two types of open-cell carbon foams, CF-1 and CF-2, with different strut diameters, were examined. The morphology and uniformity of the coatings were characterized, and the effect of coating thickness on the compressive strength of the foams was systematically analyzed. An empirical model was proposed and successfully validated, showing that the compressive strength is proportional to the coating thickness and the square of the strut diameter. The experimental results demonstrate that considering mass transfer and reaction kinetics can significantly improve the uniformity of coatings on larger substrates. Furthermore, the Ta coatings significantly increased the compressive strength of the foams, with the relationship between compressive strength, coating thickness, and strut diameter being in good agreement with the predictions of the proposed model. The study highlights the potential of tailored metallic coatings to enhance the mechanical properties of porous materials while maintaining their lightweight characteristics, emphasizing the importance of optimizing coating parameters for large-scale applications.

Electrochemical water splitting, a sustainable method for hydrogen production, faces the challenge of slow oxygen evolution reaction (OER) kinetics. Iridium oxide (IrO₂) is widely regarded as the most effective catalyst for OER due to its excellent properties. Compared to nanoparticles, IrO₂ thin films exhibit significant advantages in OER, including a uniform and stable catalytic interface and excellent mechanical strength. This paper reviews recent advancements in one-step deposition techniques for the preparation of IrO₂ thin films and their application in OER. Additionally, it analyzes the advantages and disadvantages of various methods and the latest research achievements, and briefly outlines the future trends and applications.

In this study, a HfO₂ coating was developed on an Ir matrix using a customized open-tube airflow, cold-wall chemical vapor deposition instrument. The preparation process and structure of the as-prepared coating were investigated to gain insights into its characteristics. The HfO₂ coating effectively prevents direct contact between Ir and O, leading to a reduction in the oxidation rate of Ir. Furthermore, defects such as micropores and cracks generated during sealed oxidation erosion contribute to Ir’s decelerated oxidation failure. The as-prepared HfO₂ coating exhibits low thermal conductivity and a high heat radiation rate, reducing the coating’s surface temperature. These characteristics significantly enhance adversity tolerance and increase the working temperature of the coating. Moreover, the as-prepared HfO₂ coating can serve as a diffusion barrier, blocking both the direct contact of O with the Ir coating and the diffusion of other elements to the Ir coating. As a result, the rates of diffusion of other elements to the Ir coating are reduced.

Pitch-based foam carbon, a novel lightweight material, boasts excellent mechanical and thermoelectric properties, and tantalum film deposition on its surface can further enhance its performance. However, this deposition process often suffers from non-uniform deposition and suboptimal coating quality. To address these issues, this study systematically optimized the furnace structure by tuning pipe diameter, tilt angle, and porous media height. Numerical simulations of 216 models were conducted to evaluate the effects of these parameters on axial velocity, turbulence intensity (quantified by the vortex criterion Q > 1), and reactant concentration uniformity. The results showed that pipe diameters below 70 mm increased the mean axial velocity by 8-fold compared to larger diameters, whereas tilt angles of 15° and porous media heights of 60–80 mm yielded limited velocity enhancements of only 2%. Pipe diameter was identified as the dominant factor governing flow stability, inducing up to a 300% variation in the volume fraction of Q > 1, with minimal turbulence observed at the maximum diameter. In contrast, adjustments to tilt angle and porous media height had weaker effects, altering the Q > 1 volume fraction by 26% and 5%, respectively. Smaller pipe diameter (70–80 mm) also optimized TaCl₅ concentration uniformity; tilt angles between 0° and 30° showed negligible influence, while porous media height exhibited no definitive trend. Guided by the practical priorities of process evaluation, a multi-objective optimization was performed. The globally optimal structural parameters were determined to be a pipe diameter of 70 mm, a tilt angle of 15°, and a porous media height of 60 mm, which comprehensively balance deposition uniformity, process stability, and deposition efficiency. These findings establish pipe diameter as the pivotal factor for deposition homogeneity and provide a reference scheme for the structural design of industrial tantalum deposition furnaces and lay a foundation for subsequent multi-physics coupling studies and experimental validation.

Ta/Re layered composite material is a high-temperature material composed of the refractory metal tantalum (Ta) as the matrix and high-melting-point, high-strength rhenium (Re) as the reinforcement layer. It holds significant potential for application in aerospace engine nozzles. Developing the Ta/Re potential function is crucial for understanding the diffusion behavior at the Ta/Re interface and elucidating the high-temperature strengthening and toughening mechanism of Ta/Re layered composites. In this paper, the embedded atom method (EAM) potential function for tantalum/rhenium binary alloys (Ta-Re alloys) is derived using the force-matching method and validated through first-principles calculations and experimental characterization. The results show that for the lattice constant of a bcc structure containing 54 atoms, surface formation energies per unit area of Ta-Re alloys obtained based on the potential function are 12.196 Å, E₁₀₀ = 0.16 × 10⁻² eV, E₁₁₀ = 0.10 × 10⁻² eV, and E₁₁₁ = 0.08 × 10⁻² eV, with error values of 0.015 Å, 0.04 × 10⁻² eV, 0.02 × 10⁻² eV, and 0.01 × 10⁻² eV, respectively, compared with the calculations from first principles calculations. It is noteworthy that the errors in the average binding energies of Ta-rich (Ta_39Re20, where the number of Ta atoms is 39 and Re atoms is 20) and Re-rich (Ta₂₀Re₃₉, where the number of Ta atoms is 20 and Re atoms is 39) cluster atoms, calculated by the potential function and first-principles methods, are only 1.64% to 1.98%. These results demonstrate the accuracy of the constructed EAM potential function. Based on this, three compositions of Ta-Re alloys (Ta₄₈Re₆, Ta₃₀Re₂₄, and Ta₆Re₄₈; the numerical subscripts represent the number of atoms of each corresponding element) were randomly synthesized, and a comparative analysis of their bulk moduli was conducted. The results revealed that the experimental values of the bulk modulus showed a decreasing and then an increasing tendency with the calculated values, which indicated that the potential function has a very good generalization ability. This study can provide theoretical guidance for the modulation of Ta/Re laminate composite properties.