Damage to mechanical components caused by contaminant ingress is a common failure. In response to this issue, this study introduces a synergistic abrasion reduction method based on the combined ...application of ceramic materials and surface texturing. Using cylindrical thrust roller bearings as an illustration, circular textures were applied to the raceways, and a small number of steel rollers were substituted with ceramic ones. Moreover, alumina was introduced into the lubricant as a contaminant. The frictional and dynamic performance of the "ceramic-textured surface" combination under lubricant contamination conditions was explored and compared with corresponding single abrasion reduction techniques. The synergistic abrasion reduction mechanism of the "ceramic-textured surface" combination was also examined. The findings reveal that under lubricant contamination conditions, the synergistic abrasion reduction method surpasses individual abrasion reduction methods and demonstrates a certain degree of complementarity. Compared with traditional all-steel bearings, textured bearings with four ceramic rollers have reduced the average frictional force by approximately 56.82 %, and the mass loss of the shaft washer and seat washer has been reduced by approximately 81.01 % and 80.86 %, respectively. Rolling elements treated with the synergistic abrasion reduction method exhibit enhanced resistance to abrasive particle wear. This improvement is attributed to the collaborative effects of various mechanisms, including crushing and refinement, capture and storage, grinding and finishing, as well as self-healing and smoothing.
•A synergistic wear reduction method to reduce abrasive wear is proposed.•Abrasive wear tests were carried out under rolling conditions.•The surface texture and ceramic materials are added to the rolling bearing as anti-wear measures.•The tribological behavior and dynamic performance of the synergistic anti-wear method were evaluated.•The synergistic wear reduction method exhibits better wear resistance.
Aluminum alloys are frequently utilized in aerospace and automotive manufacturing due to their high strength, excellent corrosion resistance, and ease of processing. However, their suboptimal ...tribological properties significantly restrict broader applications. Currently, laser surface microtexturing is a promising method to enhance the friction and wear resistance of materials, as well as their wettability. Nonetheless, single-mode processing often exhibits inherent limitations. This study employed electrochemically assisted laser processing to create typical microtexture grooves on aluminum alloy surfaces. Additionally, to assess the impact of various processing techniques on the alloy's surface characteristics, comparative experiments were conducted in air under identical processing conditions. The textured surfaces were analyzed using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and a white light interferometer. Contact angle measurements were used to evaluate surface wettability. Furthermore, the tribological behavior of surfaces textured by different methods was investigated under both dry and oil-lubricated conditions. Results indicated that textures produced via electrochemically assisted machining exhibited superior surface quality and enhanced oil film adherence. Notably, compared to surfaces processed in air, these textures demonstrated a lower friction coefficient and reduced wear under similar frictional conditions at lower loads. This is mainly due to the presence of electrochemical conditions that further improve the precision of laser processing. And the electrochemical reaction accelerates the material removal rate and reduces the surface roughness, so the abrasion resistance of the textured surface is improved.
•Typical microtexture grooves were created on the surface of aluminum alloy by electrochemical assisted laser machining.•Textures produced via electrochemically assisted machining exhibited superior surface quality and enhanced oil film adherence.•Combining electrochemical and laser processing techniques can result in synergistic effects that further improve wear resistance.
Surface texture plays an important role in reducing friction, which has been widely applied in mechanical equipment. In this paper, a surface texture design method for sliding friction pairs based on ...machine learning is proposed, which consists of three parts: model training and construction, texture design and result verification. Firstly, artificial neural network (ANN) and gradient boosting decision tree (GBDT) are selected as the optimal forward and reverse models respectively by comparing five machine learning models. Then the optimal forward and reverse models are combined to design surface texture and verify the design results. The results show that the combination of forward and reverse models is reliable. Lubricant viscosity and friction coefficient obviously affect the design of texture size, depth and coverage. Finally, the feasibility and effectiveness of this method are validated by friction experiments. The results provide a new approach for the design of surface texture.
Tibetan Plateau is known as the world’s third pole, which is characterized by a low population density with very limited human activities. Tibetan Plateau possesses the greatest numbers of ...high-altitude inland lakes in the world. However, no information is currently available on the characteristic of microplastic pollution in those lakes within this remote area. In this work, lakeshore sediments from four lakes within the Siling Co basin in northern Tibet were sampled and examined for microplastics (<5 mm). Microplastics were detected in six out of seven sampling sites with abundances ranging from 8 ± 14 to 563 ± 1219 items/m2. Riverine input might have contributed to the high abundance of microplastics observed in this remote area. Morphological features suggest that microplastics are derived from the breakdown of daily used plastic products. Polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyvinyl chloride were identified from the microplastic samples using laser Raman spectroscopy, and oxidative and mechanical weathering textures were observed on the surface of microplastics using scanning electron microscope. These results demonstrate the presence of microplastics even for inland lakes in remote areas under very low human impact, and microplastic pollution can be a global issue.
•Microplastics were presented in lakeshore sediments from remote lakes in Tibet Plateau.•Microplastics were detected with an average abundance up to 563 items/m2.•PE, PP, PET, PVC and PS were identified from the microplastic samples.•Surface texture of microplastics show mechanical and oxidative weathering features.
Remote lakes in Tibet Plateau were found polluted by microplastics.
Scale/scaly structures are commonly seen in living nature, such as loach and pangolin, and they generally play an important role in reducing friction between biosurfaces and their contacted ...solid/water. Hence, inspired by scale structures in biology, we propose a design of surface texturing with 3D delicate scaly structures to improve the tribological behaviors of mechanical friction interfaces under starved lubrication. Micro 3D metal printing technology was employed to fabricate the scaly textured surface. Experimental tests were performed and the results demonstrated the favorable effect of such bionic texturing on reducing friction coefficient and wear. Furthermore, corresponding FEM simulations and high-speed camera observation confirmed the amplification effect of secondary lubrication and the pre-lubrication effect as the dominating mechanisms.
•A bioinspired 3D scaly surface texturing was designed and fabricated.•Friction coefficient reduction effect of the 3D textures was demonstrated.•Amplification of secondary lubrication and the pre-wetting effect were deduced as the main mechanism.
Understanding the influence of surface properties (roughness, grooves, discrete textures/dimples) on the performance of hydrodynamically lubricated contacts has been the aim of numerous studies. A ...variety of different numerical models have been employed by many researchers in order to find optimal texturing parameters (shape, size, distribution) for best performance enhancement in terms of load carrying capacity, film thickness, friction and wear. However, the large number of different modeling techniques and complexity in the patterns make finding the optimum texture a challenging task and have led to contrary conclusions. This article outlines the research effort on surface texturing worldwide, reviews the key findings and, in particular, provides a comparative summary of different modeling techniques for fluid flow, cavitation and micro-hydrodynamic effects.
•This article facilitates the application of textures for hydrodynamic contacts.•Functions of surface textures, texture design and modeling techniques are discussed.•Textures must be designed for a given application and range of operating conditions.•Robust models allow the evaluation of texture designs prior to being manufactured.•The three major challenges in numerical modeling are discussed.
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