Current Issue : April-June Volume : 2026 Issue Number : 2 Articles : 5 Articles
To extend the service life of sensors in seawater, this work prepared an integrated diffusionplated Al2O3 film using high-power impulse magnetron sputtering (HiPIMS). The tribological properties of the Al2O3 film in a marine environment were tested using a tribometer. The morphology and evolution of the Al2O3 film before and after the friction tests were investigated by characterization techniques such as field emission scanning electron microscopy (FESEM). The results demonstrate that the Al2O3 film exhibits excellent tribological performance in the marine environment, significantly enhancing the wear resistance of the substrate material. Furthermore, with the protection of the Al2O3 film, the designed pressure sensor achieved high-sensitivity detection of minute operational forces underwater. When applied to a robotic gripper for manipulation tasks, the coated underwater sensor enabled accurate perception of subtle motion states of the grasped objects....
FeCoCrNiNbxN (x = 0, 0.25, 0.5, 0.75, 1 molar) high-entropy nitride (HEN) films were fabricated on 304 stainless steel and Si wafers using magnetron sputtering to investigate the influence of Nb content on the microstructure, mechanical properties, and tribological performance. X-ray diffraction (XRD) analysis reveals a face-centered cubic (FCC) structure with a preferred orientation in the (200) plane, which transfers to the (111) plane as the Nb content increases. The lattice distortion induced by Nb incorporation enhanced crystallinity, with the Nb0.5N film exhibiting the highest diffraction peak intensity and interplanar distance. Cross-sectional SEM images displayed columnar crystal structures, while the surface morphology evolved from “cauliflower-like” to smoother clusters with increasing Nb content, reducing average roughness from 7.54 nm (Nb0) to 4.89 nm (Nb1). The hardness and elastic modulus initially decrease, then peak at 25.56 GPa and 265.36 GPa, respectively, for the Nb1 film, attributed to solid solution strengthening and high-entropy effects. Tribological tests demonstrated that Nb1 achieved the lowest coefficient of friction (0.46), wear volume (1.23 × 10−3 mm3), and wear rate (5.11 × 10−8 mm3·N−1·m−1), owing to NbN phase formation, refined grains, and reduced surface roughness. The wear mechanisms are abrasive and oxidative wear....
This study focuses on surface modification of aluminum alloys (Al–Si) with high silicon content using plasma electrolytic oxidation (PEO). The influence of Al2O3 and SiO2 particles, introduced both separately and in combination, into a sodium aluminate-based electrolyte during high-frequency treatment (2000 Hz). Examination of surface and cross-sections using a scanning electron microscope SEM showed an increase in the compactness of the coating when Al2O3 particles were introduced. The addition of SiO2 particles tended to promote a smoother surface and a slight reduction in the porosity and defect density. However, when these particles are added together, especially at high concentrations, an increase in structural defects and crack formation is observed. X-ray diffraction analysis revealed that the γ-Al2O3 phase was present in all coatings. In the samples with Al2O3 addition, the α-Al2O3 diffraction signal became stronger compared with the other coatings. Tribological tests revealed that the addition of Al2O3 particles significantly improved wear resistance, while the introduction of SiO2 particles contributed to the stabilization of the friction coefficient. Thus, Al2O3 particles were the most effective in enhancing the mechanical properties of the coating....
Background: Cu-based friction materials (CBFMs) exhibit significant application in transportation and mechanical engineering due to their excellent wear resistance, thermal conductivity, and stable tribological performance. Methods: In this study, CBFMs holding a 3D mesh reinforcement structure was prepared under different sintering temperatures and sintering times. The phase, mechanical, and tribological properties were tested, and the wear mechanisms were analyzed. Results: The results showed that with an increase in sintering temperature, compressive strength showed a trend of increasing first and then decreasing, COF showed a decreasing trend first and then an increasing trend, and wear rate showed a decreasing trend that can be attributed to the different strength of the matrix and 3D mesh reinforcement structure at different sintering temperatures. With an increase in sintering time, COF continuously increased and wear rate sustained a decrease. Conclusions: Compared with previous studies, this study revealed the influence mechanism of sintering temperature and sintering time on the comprehensive properties of CBFMs holding a 3D mesh reinforcement structure for the first time. The results can provide data support for the performance improvement of CBFMs holding a 3D mesh reinforcement structure, and lay a theoretical foundation for the further study of powder metallurgy materials....
Fe-Cr-Al coatings were obtained by air plasma spraying (APS) from 85Fe-12Cr-3Al and 68Fe-26Cr-6Al powders at two hydrogen flow rates (8 and 13 L/min), which resulted in four deposition regimes (A1, A2, B1, B2). Stainless steel 20Kh13 (equivalent to AISI 420) was used as the substrate material. The microstructure of the coatings has a typical lamellar layering with molten and semi-molten particles. When the hydrogen flow rate is increased to 13 L/min, a denser and more homogeneous structure with reduced porosity is observed. X-ray phase analysis revealed the presence of metal and oxide phases (Fe,Cr), Fe3O4, FeO, Fe2+Cr2O4, which indicates partial oxidation of particles during the spraying process and stabilization of the structure. Electrochemical tests in 3.5% NaCl solution showed that the 85Fe-12Cr-3Al coatings are characterized by a corrosion potential of Eo ≈ −0.60. . .−0.67 V, a corrosion current density of io = (2.6–4.7) × 10−5 A/cm2, and a corrosion rate of 0.30–0.55 mm/year, whereas the 68Fe-26Cr-6Al coatings exhibit lower values of io = (1.4–2.9) × 10−5 A/cm2 and a corrosion rate of 0.17–0.34 mm/year, indicating the formation of a denser protective oxide film (Cr2O3 + Al2O3) and enhanced surface passivation. Tribological tests showed that 85Fe-12Cr-3Al coatings demonstrate more stable friction compared to 68Fe-26Cr-6Al, while for regime B2, after 180 m, an increase in the friction coefficient is observed, caused by brittleness and the local destruction of the oxide film. A comprehensive analysis of the results showed that increasing the hydrogen consumption to 13 L/min improves the density and corrosion–tribological characteristics of the coatings....
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