Laser texturing technology utilizes high-energy laser beams to generate specific microstructures on the material surfaces, improving their friction and wear properties. This study investigates the effects of nanosecond pulsed laser texturing on the surface characteristics of chromium-plated alloys with a focus on changes in processing dimensions and surface morphology. A systematic experimental analysis was conducted to determine the optimal range of process parameters. This study primarily examines the influence of laser power, scanning speed, repetition frequency, and pulse width on the friction and wear properties of materials. The results demonstrate that surface texturing significantly improves the wear resistance. When the laser energy per unit area is high and the pulses are more concentrated, the wear resistance of the textured surface increases. Conversely, lower laser energy and more dispersed pulses result in reduced wear resistance. Optimized surface texturing parameters enhance wear resistance and minimize coating detachment during wear, providing valuable insights for improving the durability of chromium-plated alloys in high-friction applications.

This paper explores the characteristics of processing carbon fiber-reinforced plastic (CFRP) materials with ultra-short pulsed lasers. By combining experimental and numerical simulation methods, the processing characteristics when ultra-short pulsed lasers interact with CFRP are analyzed, including processing depth, processing width, the formation of heat-affected zone (HAZ), and the microstructure of the processed surface. The experimental part involves using picosecond and femtosecond lasers to machine holes or slots in CFRP under different process parameters and comparing their morphologies. Numerical simulation constructs a three-dimensional model to predict the temperature field distribution and material removal dynamics during the laser processing process. The results of experiments and simulations indicate that picosecond laser processing produced a visible HAZ and thermal damage; as the power of the picosecond laser increases, the ablation holes and HAZ gradually expand. In contrast, no HAZ is observed in femtosecond laser processing. Femtosecond pulsed lasers can effectively reduce the thermal damage during the CFRP processing. The anisotropic properties of CFRP materials have a significant impact on the laser processing effects. The research findings provide a theoretical basis and technical support for the precise processing of CFRP materials, which is of great significance for the application of CFRP materials in fields such as aerospace and automotive manufacturing.

This study aimed to analyze the effects of surface texture on the wear amount of floating oil seals and how these effects are related to the texture parameters. To achieve this, a finite element model was constructed to simulate the frictional behavior of seal discs under both textured and non-textured conditions. The study focused on a specific set of texture parameters. The texture depth was held constant, while the area density and diameter of the textures were varied. Three different area densities were considered: 10%, 20%, and 30%. Similarly, three different texture diameters were included in the study: 100, 200, and 300 μm. For each combination of area density and diameter, three different texture depths were evaluated: 50, 100, and 150 μm. The results show that compared with the non-texture, the wear loss of the texture is significantly reduced, and the wear loss is reduced by 56.8%. As the texture depth increases, the corresponding increase in wear remains relatively small. In contrast, increasing the texture diameter and area density leads to a more significant increase in wear, indicating that these two parameters have a more significant effect on the wear behavior of the seal. Under the condition of dry friction, the average friction coefficient analysis shows that the texture area density is 30%, the texture diameter is 200 μm, and the minimum value is about 0.602. Under the lubrication condition, the lowest average friction coefficient is about 0.147, the texture area density is 20%, and the texture diameter is 300 μm.

The increasing demand for high-performance aircraft engines has led to a greater emphasis being placed on advanced sealing coating technologies. Developing long-life, self-lubricating, and wear-resistant coatings is of significant research value. This study focuses on the fabrication of a novel self-lubricating and wear-resistant NiCoCrAlY-Cr₂O₃-AgMo composite coating. This coating was deposited onto a GH4169 substrate utilizing plasma spraying. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) and X-ray diffraction (XRD) methods were employed to characterize the elemental composition and microstructure of the fabricated NiCoCrAlY-Cr₂O₃-AgMo composite coating. Microhardness measurements across the coating cross-section indicated a gradual increase in hardness from the GH4169 substrate to the NiCoCrAlY-Cr₂O₃-AgMo coating. The average hardness of the GH4169 substrate was 413.92 HV_0.2, while the CoNiCrAlY bonding layer region exhibited an average hardness of 467.60 HV_0.2. The NiCoCrAlY-Cr₂O₃-AgMo coating itself demonstrated an average microhardness of 643.22 HV_0.2. Room temperature friction tests indicated that the average coefficient of friction (COF) of the GH4169 substrate was 0.665. In contrast, the NiCoCrAlY-Cr₂O₃-AgMo coating exhibited a significantly lower average COF of 0.16, representing a 75.94% reduction compared to the uncoated GH4169 substrate. High-temperature friction tests were conducted at 400 °C, 500 °C, and 600 °C, indicating average COF values of 0.438, 0.410, and 0.268, respectively, for the NiCoCrAlY-Cr₂O₃-AgMo coating. Specifically, at 600 °C, the formation of a lubricious NiMoO₄ tribofilm on the coating surface was observed. This tribofilm effectively reduced the wear rate of the GH605 pin to 2.78 × 10⁻⁶ mm³/N·m, highlighting the potential of the NiCoCrAlY-Cr₂O₃-AgMo coating to reduce wear in high-temperature sliding contact applications.

This study investigates the effects of the nanosecond pulse laser parameters on the processing characteristics of carbon fiber-reinforced carbon matrix (C/C) composites through a series of laser cutting experiments. It compares the cutting width, depth, heat-affected zone (HAZ) width, processed surface micro-morphology, as well as the oxidation characteristics of the material under different processing parameters. The HAZ width is analyzed in relation to the variations in the oxygen content. The results indicate that both the cutting width and depth initially increase and then decrease with increasing repetition frequency. Moreover, increasing the laser power and pulse width gradually increases the cutting width, depth, and HAZ width, whereas a higher scanning speed tends to reduce the cutting width and depth. Since changes in the processing power, scanning speed, and pulse width affect the HAZ, the oxygen content exhibits a proportional relationship with the HAZ width. In addition, an increase in the repetition frequency can expand the HAZ while reducing the oxygen content. A careful increase in the repetition frequency aids in lowering the ablation threshold of the material, leading to more material removal. Nevertheless, a continuous increase in energy density can trigger a fiber pull-out phenomenon and cause degradation of the matrix.

The finger seal is an important type of dynamic seal in aeroengines carbon fiber-reinforced carbon matrix (C/C) composites have self-lubrication and elasticity that match the application environment of the finger seal. They can not only reduce fuel consumption by decreasing the weight but also effectively improve the load capacity of the sealing device on the basis of low leakage. In this study, a simulation model for laser cutting of C/C composite finger seal was established based on the finite element method. The effects of processing power and processing speed on cutting quality were investigated through simulation analysis, and key indicators such as surface morphology, elemental content, and kerf taper were examined through experiments. The results show that the cutting quality can be regulated by reasonably selecting processing power and processing speed. A narrow kerf can be obtained at low power, and surface roughness can be reduced at high speed. In addition, the consistency between experimental data and simulation results is good, and the accuracy of the simulation results was verified by comparative experiments.