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•A new composite material composed of thermoplastic polyurethane, tetra-needle zinc oxide whisker, and molybdenum disulfide was fabricated.•Tetra-needle zinc oxide whisker reduced the ...deformation behavior of the wear surface, coefficient of friction, and fluctuation range, resulting in the reduction of frictional vibration.•Molybdenum disulfide enhanced the self-lubricating properties of thermoplastic polyurethane, and peeled off and transferred to the contact surface, resulting in low and stable coefficient of friction behaviors.•The synergistic effect of 6% tetra-needle zinc oxide whisker and 9% molybdenum disulfide possessed the best frictional vibration reduction properties.
A novel thermoplastic polyurethane (TPU) matrix composite was combined with tetra-needle zinc oxide whisker (T-ZnOw) and molybdenum disulfide (MoS2) particles. Frictional vibration experiments were conducted to study the effect of T-ZnOw and MoS2 particles on frictional vibration behaviors. The tribological properties and vibration behaviors of TPU composites were synthetically analyzed to reveal the effects of T-ZnOw and MoS2 on the friction excitation force and vibration reduction properties. The results showed that T-ZnOw enhanced anti-deformation property, and MoS2 weakened the friction excitation force in the friction process, which resulted in a lower coefficient of friction (COF) with a small amplitude, and eliminated the high-frequency vibration amplitude. In addition, the particle composition of 6% T-ZnOw and 9% MoS2 was controlled to obtain a low COF and the best vibration reduction properties. The knowledge obtained herein contributes to the understanding of the synergistic effects of T-ZnOw and MoS2 on COF and vibration reduction behaviors, and the development of a water-lubricated TPU composite stern tube bearing with low COF and good vibration reduction properties.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Frictional vibration and noise usually cause machining error and noise pollution. Stick–slip plays an important role in generating frictional vibration and noise. This study characterized frictional ...vibration and noise during the stick–slip of a Si
3
N
4
ceramic/metal friction by using an acoustic emission method. Experimental results showed that frictional vibration and noise mostly occurred during the slip process. The impacts of the rough peaks between metal disk and ceramic ball during sliding induced the vibration to irradiate noises. The superposition among the frictional vibrations caused the multiplication of vibrational frequency. The major vibrational frequency slowly shifted to a higher frequency as the increase in sliding speed. The vibrational accelerations and their major vibrational frequency increased with the increase in the external load. The knowledge gained herein provides a more comprehensive understanding of stick–slip friction, frictional vibration, and noise, and offers a guidance for controlling or minimizing stick–slip, frictional vibration, and noise.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The insufficient lubrication of the contact interface between moving parts can easily induce severe friction vibration and noise under extreme working conditions, which will threaten the service life ...and reliability of polymer moving components, including water-lubricated stern tube polymer bearings. Thermoplastic polyurethane (TPU) modified by polytetrafluoroethylene (PTFE) particles was developed. The effects of PTFE on the wear and vibration behaviors of modified TPU sliding against the ZCuSn
Zn
ring-plates were investigated. The coefficients of friction (COFs), wear mass losses, wear morphologies, frictional vibration, and noise were analyzed synthetically. The results showed that a suitable mass content of PTFE reduced the COFs and wear mass losses of the TPU composites by more than 50% and 40%, respectively, while presenting an excellent friction reduction. The lower COFs of modified TPU showed a small fluctuation amplitude and eliminated vibration waveforms at high vibrational frequencies, which was useful for reducing frictional vibration and noise. The knowledge gained in this study is useful for a better understanding of the wear behaviors of polymer composites, as well as for the design a new polymer material with good self-lubricating and frictional vibration and noise reduction properties.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Lignum vitae was widely applied in water-lubricated bearing because of its green, pollution-free, excellent mechanical, and self-lubricating properties. The slow growth cycle is difficult to meet the ...bearing's rapid development. Lignum vitae chips were used to modify thermoplastic polyurethane (TPU) to extend its good self-lubricating properties and improve tribological behaviors. The results showed that lignum vitae improve TPU's shore hardness, elastic modulus, and elongation, but at the slight cost of tensile strength and thermal stability. Besides, lignum vitae chips endowed TPU with good hydrophilicity and water absorption properties, which conduced to form effective lubricating film and reduced COF behaviors. TPU with 6% lignum vitae chips had the best COF reduction and wear resistance. But excessive lignum vitae chips weakened elastic modulus and elongation to increase COF behaviors and wear process. The outcome obtained herein would provide strong theoretical guidance for developing novel green and sustainable composites with excellent tribological properties.
•A novel green TPU matrix water-lubricated bearing was fabricated by adding lignum vitae chips.•Lignum vitae possessed many polar bonds and hydrophilic functional groups.•Lignum vitae chips endow TPU with hydrophilicity and excellent water absorption properties.•TPU with 6 wt% lignum vitae chips presented the best COF reduction and wear resistance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Several soft tissues residing in the living body have excellent hydration lubrication properties and can provide effective protection during relative motion. In order to apply this advantage of soft ...matters in practical applications and try to avoid its disadvantage, such as swelling and weakening in water, a design strategy of a soft/hard double network (DN) hydrogel microsphere modified ultrahigh molecular weight polyethylene (UHMWPE) composite is proposed in this study. A series of microspheres of urea-formaldehyde (UF), polyacrylamide (PAAm) hydrogel, UF/PAAm double network, and their composites were prepared. The mechanical properties, swelling, wettability, friction properties, and the lubrication mechanisms of the composites were investigated. The results show that DN microspheres can have an excellent stability and provide hydration lubrication. The performance of 75 DN-1 composite was superior to others. This finding will provide a novel strategy for the development of water-lubricated materials and have wide application in engineering fields.
Natural materials tend to exhibit excellent performance in the engineering field because of their structure and special functions. A natural red willow, called natural porous wood material (NPWM), ...was found, and wear tests were conducted to determine its potential as an oil-impregnated material by utilizing its special porous structure. Fluorination treatment was adopted to improve the NPWM properties for absorbing and storing lubricating oil. The different contributions of soaking and fluorination-soaking treatments on the tribological properties of NPWMs and their respective mechanism of effect were revealed. The results showed that the fluorination-soaking treatment helped absorb and store sufficient lubricating oil in the NPWM porous structure; therefore, more lubricating oil would be squeezed out and function as a tribol-film between contacting surfaces during the friction process, thus ultimately contributing to stable and smooth wear responses even under prolong friction. However, the formation of an oil-in-water emulsion, caused by the buoyancy effect, destroyed the oil films on the worn NPWM surface in a water environment, resulting in higher coefficients of friction (COFs) under water conditions than under dry friction, even after the fluorination-soaking treatment. The knowledge gained herein could not only verify the potential of NPWM as an excellent oil-impregnated material in the engineering field but also provide a new methodology for the design of artificial porous materials with stable and smooth friction processes.
Reducing the deformation of polymer matrix materials can decrease the fluctuation of coefficient of friction (COF), and friction-induced vibration and its amplitudes. HDPE composites with T-ZnOw as a ...fixed strengthening filler were modified with the addition of Si
N
particles at different concentrations. The COFs, wear rates, micro-morphologies, and friction-induced vibrations were obtained by conducting sliding tests against carbon steel balls in an aqueous environment at a low velocity and high load. The mechanism of the reduction in frictional fluctuation due to the addition of Si
N
particles was revealed through the frictional responses. The results demonstrated that 4 wt% addition of Si
N
in HDPE can enhance the strain-stress property and improve the lubrication by forming a lubricating film. Therefore, the surface deformation and the fluctuations of COFs and its vibrations were reduced. The aggregation phenomenon and reduced strain-stress response at a high concentration of Si
N
disrupted the positive fluctuating reduction, and resulted in a rough surface with severe tearing and cracking deformations. Additionally, it led to fluctuating wear behaviors with high COF and vibrations. The results obtained in this study can elucidate the effects of adding Si
N
particles to enhance lubrication in polymer composites. Additionally, the results provide a new research method for designing and manufacturing polymer-based composites with low friction-induced fluctuations.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
With the development of green tribology in the shipping industry, the application of water lubrication gradually replaces oil lubrication in stern bearings and thrust bearings. In terms of ...large-scale and high-speed ships, water-lubricated bearings with high performance are more strictly required. However, due to the lubricating medium, water-lubricated bearings have many problems such as friction, wear, vibration, noise, etc. This review focuses on the performance of marine water-lubricated bearings and their failure prevention mechanism. Furthermore, the research of marine water-lubricated bearings is reviewed by discussing its lubrication principle, test technology, friction and wear mechanism, and friction noise generation mechanism. The performance enhancement methods have been overviewed from structure optimization and material modification. Finally, the potential problems and the perspective of water-lubricated bearings are given in detail.
Stainless steel is widely used in strongly oxidizing hydrogen peroxide (H
O
) environments. It is crucial to study its wear behaviour and failure mode. The tribological properties and oxidation of ...304 stainless steel were investigated using a MMW-1 tribo-tester with a three-electrode setup in H
O
solutions with different concentrations. Corrosion current densities (CCDs), coefficients of frictions (COFs), wear mass losses, wear surface topographies, and metal oxide films were analysed and compared. The results show that the wear process and oxidation process interacted significantly with each other. Increasing the concentration of H
O
or the oxidation time was useful to form a layer of integrated, homogeneous, compact and thick metal oxide film. The dense metal oxide films with higher mechanical strengths improved the wear process and also reduced the oxidation reaction. The wear process removed the metal oxide films to increase the oxidation reaction. Theoretical data is provided for the rational design and application of friction pairs in oxidation corrosion conditions.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The tribological properties of ZrO
2
ceramic and 1Cr18Ni9Ti stainless steel rubbing pairs were investigated using a special tribotester under different concentrations of hydrogen peroxide (H
2
O
2
) ...solution. The comparison analyses of the friction coefficients, worn volume rates, worn particles and surface roughness were conducted under the tested conditions. There were significant differences of the tribological properties of the rubbing pairs in the different concentrations H
2
O
2
solution because of oxidation and corrosion. This research has revealed that the main wear mechanisms between the rubbing pairs are severe adhesive wear, abrasive wear and corrosive wear in the H
2
O
2
solution with different concentrations. A model has been established to assess the most suitable concentration of the H
2
O
2
solution for the tribological properties of the rubbing pairs. The result shows that 50% concentration of the H
2
O
2
solution is the most suitable. The assessment result is consistent with the experimental result. It is believed that the knowledge gained in this study is useful for the optimization of the friction pairs in the extreme condition.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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