Current Issue : July-September Volume : 2025 Issue Number : 3 Articles : 5 Articles
The slip mechanism between the chunk and wafer during high-speed dynamic scanning of the extreme ultraviolet lithography (EUV) motion stage remains unclear. Considering real-machined roughness, molecular dynamics (MD) simulations were performed to investigate the nanotribological behavior of 6H-SiC sliders on single-crystal silicon substrates. The effects of sinusoidal asperity parameters and normal loads on wear and slip were systematically analyzed. Results indicate that, for friction between sinusoidal asperities and ideal flat surfaces, the amplitude of surface parameters exhibits negligible influence on friction. In contrast, reduced normal loads and lower periods significantly increase both friction force and coefficient of friction (COF)....
The setae structure of geckos’ toes can create a strong adhesion force, allowing geckos to climb almost vertical walls. Inspired by this, carbon nanotubes–graphite (CNTs-Gr) was prepared by microwave technology, where CNTs like the setae structure grew in situ on the surface of Gr flakes. Compared to the Gr, the coefficient of friction (COF) and wear rate of CNTs-Gr decreased by 44% and 46%, reaching 0.10 and 1.18 × 10−5 mm3·N−1·m−1, respectively. Even if the load increased from 5 N to 35 N, the CNTs-Gr maintained a low and stable COF of 0.12. The excellent tribological properties were attributed to the unique setae structure of CNTs-Gr. This structure enabled the adhesion force of CNTs-Gr to the worn surface to increase threefold, improving the coverage of the lubricating film and significantly enhancing the lubricating film’s pressure resistance. The gecko setae structure proposed in this article provides researchers with a new idea for designing lubricants with excellent lubrication performance and high load-bearing capacity....
The present study reports the tribological properties and residual stress of titanium chromium nitride (TiCrN) coatings. Thin films of TiCrN were deposited on tungsten carbide substrates at 400 ◦C in a vacuum of 5 × 10−6 mbar using the cathodic-arc physical vapor deposition technique with chromium variation. X-ray diffraction (XRD) spectroscopy was employed to probe the structures of the deposited thin films. The phase constituent was found to gradually shift from cubic TiN to cubic CrN. Both the hardness and elastic modulus of the sheet changed from 29.7 to 30.9 GPa and 446 to 495 GPa, respectively. The biaxial compressive residual stress after an initial absolute scan in the range of 30–100◦ was determined using XRD (d-sin2ψ method). These mechanical and tribological properties of films were investigated with the help of instrumented nanoindentation and a ball-on-disk tribometer wear test. The wear test indicates that the TiCrN thin film, featuring a Cr/Ti ratio of 0.587, exhibits superior wear resistance and maximum compressive residual stress in comparison to other thin films....
Adding alloying elements to binary nitrides enables the design of hard and tough coatings. To improve the mechanical and tribological performances of TiN-based coatings, La atoms were added to TiAlN coatings to form TiAlLaN coatings. Magnetron sputtering was conducted to prepare the TiAlLaN coatings. Thereafter, scanning electron microscopy (SEM), x-ray diffraction (XRD), nano-indentation, and a tribometer were utilized to test their microstructure, phases, and mechanical and tribological performances. Next, this study analyzed how lanthanum affected the microstructure and tribological performances of the TiAlLaN coatings. Incorporating La atoms in TiAlN coatings reduced the crystallite size and enhanced the coating toughness and hardness. The hardness H and elastic modulus E of the TiAlLaN coatings first increased and then decreased with the increase in La. Meanwhile, the coatings had improved wear and friction properties. The increased H/E and H3/E2 levels, which have been considered to reflect the hard coating’s toughness, were acquired based on the TiAlLaN coating, possessing enhanced hardness (19.8 GPa). The coefficient of friction and the wear rates of the coatings reduced and then increased with the increase in La. The TiAlLaN coating with 1.4 % of lanthanum had the lowest friction coefficient and wear rate of around 0.383 and 1.59 × 10−8 mm3/N·m, respectively, corresponding to a higher H/E (~0.086) and H3/E2 (~0.147 GPa). Adding an appropriate amount of La can substantially enhance the TiAlN coating’s tribological and mechanical properties. The TiAlLaN coating with remarkable characteristics may be applied to a steel substrate....
A new shearing tool is necessary to reduce the iron loss of motor cores by minimizing the work hardening damage on the sheared non-oriented electrical steel sheets. The punch edge topology and the clearance between the punch and the die were controlled to investigate their influence on the sheared surface condition and the work hardening damage of steel sheets. A non-oriented electrical steel sheet with the thickness of 500 μm was used and sheared at the speed of 5 mm/s. After that, the sheared surface was investigated. In particular, hardness mapping was utilized to quantitatively analyze the work-hardened area of the sheared steel sheets and the dissipation of the plastic work. Among the four punch edge topological configurations explored, the nano-grooved punch employed straight along the shearing direction reduced the damage dealt to the sheared steel sheets and the plastic dissipation work to one-third compared to conventional punches....
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