Friction and Wear Behaviors of Solid Lubricants/Polyimide Composites in Liquid Mediums

2010 ◽  
Vol 654-656 ◽  
pp. 2763-2766 ◽  
Author(s):  
Li Wen Mu ◽  
Xin Feng ◽  
Yi Jun Shi ◽  
Huai Yuan Wang ◽  
Xiao Hua Lu
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Alkaline Solution ◽  
Dry Friction ◽  
Friction And Wear ◽  
Solid Lubricants ◽  
Polyimide Composites ◽  
Inorganic Fillers ◽  
Ptfe Composites

The tribological properties of polyimide (PI) composites reinforced with graphite or MoS2 sliding in liquid alkali and water as well as dry friction were investigated using a ring-on-ring tester. The results show that the friction coefficient (μ) and wear rate (W) for both graphite/PI and MoS2/PI composites in different liquid mediums are μdry>μwater >μalkali and Wwater>Wdry >Walkali. Results also indicate that the friction coefficient and wear rate of the PI composites filled with different solid lubricants are μMoS2 >μgraphite and W MoS2 >Wgraphite in different liquid mediums. In addition, the hydrophobic inorganic fillers are fit for the reinforcement of polymer-based composites sliding in liquid mediums. It is also concluded from the authors’ work that the wear rate and friction coefficient of polymer-based (such as PI, PTFE) composites in the alkali lubricated conditions is lowest among all the friction conditions. This may be attributed to the ionic hydration in the alkaline solution.

The influence of laser surface texture on the tribological properties of friction layer materials in ultrasound motors

2021 ◽  
pp. 135065012110527
Author(s):  
Xijun Hua ◽  
Julius Caesar Puoza ◽  
Peiyun Zhang
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Dry Friction ◽  
Friction And Wear ◽  
Ultrasonic Motor ◽  
Area Ratio ◽  
Ultrasonic Motors ◽  
Increase Rate

Ultrasonic motors are typically driven by the dry friction force between the rotor and the stator; the friction pairs’ high friction coefficient and low wear rate are two essential elements for improving the operational stability with longer service life. In this research article, high-precision microgroove arrays were manufactured on the surfaces of the stator and rotor of the TRUSM60 ultrasonic motor using laser machining. Dry friction and wear tests between the stator and the rotor were carried out with pin-on-disc using HSR-2M high-speed reciprocating friction and wear tester to determine the tribological properties of the ultrasonic motor. According to a different distribution of microgrooves on the two contact surfaces, the influence of smooth surface, single-sided texture, and double-sided texture on the friction pair's friction performance were discussed. The results show that the textured surface can substantially increase the coefficient of friction of the contact surface and reduce the rate of wear. The one-sided textured phosphor bronze surface with a microgroove width of 200μm and an area ratio of 20% had the highest coefficient of friction of 0.334 and a friction increase rate of 36.3%. Similarly, the single-sided textured Polyimide surface attained the highest friction coefficient of 0.355 and friction increase rate of 44.9% when the groove width is 150μm and the area ratio is 30%. A higher friction coefficient of the double-sided texture can be obtained through reasonable parameter configuration than the single-sided texture. The included angle of 0° between the two textured surfaces produced the highest friction coefficient of 0.368 and the wear rate of the phosphor bronze and polyimide surfaces were 2.01 × 10−4 mm3/N-m and 1.949 × 10−3 mm3/N-m, respectively. The result provides an essential benchmark for enhancing the tribological performance of ultrasonic motors and increasing the output torque.

scholarly journals Fabrication and Tribological Properties of Copper Matrix Solid Self-Lubricant Composites Reinforced with Ni/NbSe2 Composites

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1854
Author(s):  
Fei-xia Zhang ◽  
Yan-qiu Chu ◽  
Chang-sheng Li
Keyword(s):  
Powder Metallurgy ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Friction And Wear ◽  
Copper Matrix ◽  
Wear Properties ◽  
Disk Friction ◽  
Friction Reducing ◽  
Properties Of Composites

This paper presents a facile and effective method for preparing Ni/NbSe2 composites in order to improve the wettability of NbSe2 and copper matrix, which is helpful in enhancing the friction-reducing and anti-wear properties of copper-based composites. The powder metallurgy (P/M) technique was used to fabricate copper-based composites with different weight fractions of Ni/NbSe2, and tribological properties of composites were evaluated by using a ball-on-disk friction-and-wear tester. Results indicated that tribological properties of copper-based composites were improved by the addition of Ni/NbSe2. In particular, copper-based composites containing 15 wt.% Ni/NbSe2 showed the lowest friction coefficient (0.16) and wear rate (4.1 × 10−5 mm3·N−1·m−1) among all composites.

Effects of Elements Composition on Tribological Properties of PES/Metal Matrix Composite Materials

2013 ◽  
Vol 313-314 ◽  
pp. 188-192
Author(s):  
Zhi Gao Luo ◽  
Jin Li ◽  
Bing Zhao ◽  
Jian Wei Xu
Keyword(s):  
Composite Materials ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Tribological Properties ◽  
Metal Matrix ◽  
Friction And Wear ◽  
Plastic Layer ◽  
Test Machine

The friction and wear characteristics of PES/metal matrix composite materials were tested by the ball-disc friction pair of UMT-2 friction and wear test machine. The plastic layer is composed of distinct components. The results showed that: the tribological properties of PES/metal matrix composites were improved significantly after added 5wt % of the LCP. With the increasing of PTFE the PES/metal matrix composite material friction coefficient and wear rate were decreasing when the load of 10N and rotating speed of 400rmp. But the friction coefficient and wear rate increased when the mass fraction of PTFE more than 22 wt %. The tribological properties were the best when the PTFE content was 18 wt % to 25 wt % in the plastic layer.

Reciprocating friction and wear of polyimide composites filled with solid lubricants

2018 ◽  
Vol 38 (4) ◽  
pp. 363-370 ◽  
Author(s):  
Jingfu Song ◽  
Gai Zhao ◽  
Qingjun Ding ◽  
Jinhao Qiu
Keyword(s):  
Friction Coefficient ◽  
High Performance ◽  
Friction And Wear ◽  
Solid Lubricants ◽  
Friction Reduction ◽  
Frictional Material ◽  
Performance Engineering ◽  
Ultrasonic Motors ◽  
Polyimide Composites ◽  
Engineering Polymers

AbstractHigh-performance engineering polymers are a potential frictional material candidate for mechanical systems with moving parts, especially at high load and speed conditions. In this study, reciprocating friction and wear of aramid fibers/polyimide composites filled with graphite, MoS2or Polytetrafluoroethylene, respectively, were systematically investigated on a Pin-on-Flat test rig. The experimental setup was simplified into friction materials reciprocating against a phosphor bronze pin to simulate the rotor/stator contact state in ultrasonic motors. A comparative study on friction reduction and wear resistance of polyimide composites indicated that graphite showed the best lubricity with low friction coefficient and wear rate. Experimental results of pressure time average velocity measurements showed that frequencies ranging from 3 to 11 Hz played a significant role on the friction coefficient variations of these porous polyimide composites, whereas increasing pressure from 4 to 6 MPa had little effect on friction reduction. Then, the microstructure of the worn surface of the three different materials was observed by scanning electron microscope to reveal the wear mechanisms. This study is expected to provide a good guidance for porous polyimide composites application in ultrasonic motors.

scholarly journals Tribological Properties of Al-Based Composites Reinforced with Fullerene Soot

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6438
Author(s):  
Firuz Yunusov ◽  
Tatiana V. Larionova ◽  
Oleg Tolochko ◽  
Alexander D. Breki
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Composite Materials ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Friction And Wear ◽  
Pure Aluminum ◽  
Fullerene Soot ◽  
Scanning Electron

Aluminum-based composite materials reinforced with fullerene soot, which is a mixture of fullerene and amorphous carbon, are promising materials for friction and wear applications. Composite materials: aluminum with 2% fullerene soot (f.s) and Al with 2% f.s and 2% Cu were obtained via mechanical milling followed by hot pressing. The tribological properties (friction and wear) of the listed composites were investigated and compared with the results for pure aluminum obtained under similar conditions. It has been shown that the addition of fullerene soot reduces the friction coefficient by 25%. At additional alloying with copper, the friction coefficient decreased by 35% in comparison with pure aluminum and also lad to a decrease in friction fluctuations. The wear rate of composite Al with 2% f.s decreased twice in comparison with that of pure aluminum, and with additional alloying it decreased 2.5 times. The morphology of the wear surfaces was investigated by scanning electron microscopy (SEM). The influence of fullerene soot and additional alloying on the wear mechanism was shown.

Tribological Properties Between a-C:H Coatings and SiO2 at High Temperature

2020 ◽  
Author(s):  
Noritsugu Umehara ◽  
Kota Konishi ◽  
Motoyuki Murashima ◽  
Takayuki Tokoroyama
Keyword(s):  
High Temperature ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Friction And Wear ◽  
Wear Track ◽  
Severe Damage ◽  
Friction Test ◽  
Low Friction ◽  
Disk Friction

Abstract Tribological properties of a-C:H coatings has been investigated in various friction conditions. It is clear that temperature and mating materials give effects on tribological properties. In this study, we especially focus on the effect of mating material on its tribological properties of a-C:H coatings. Ball-on-disk friction test is conducted between a-C:H coating and 5 kinds of mating material, which is SiC, SiC(O)_800 (SiC oxidized at 800°C), SiC(O)_1050°C, SiC(O)_1300°C, and Quartz glass. It is found that a-C:H coatings shows low friction coefficient and low specific wear rate when O/Si ratio of the element content of mating material is 2, in other words, mating material is SiO2. In the wear scar of a-C:H coating after friction test with SiC, severe damage was confirmed. It is considered that a-C:H coating and SiO2 show low adhesion even at high temperature, which leads low friction and wear. Compared SiC(O) with Quartz, the friction coefficients with a-C:H coatings are respectively 0.013 and 0.038. Even though SiC(O) and Quartz are both SiO2, the tribological properties are different. On the wear track of SiC(O), transferred things from a-C:H coating are confirmed.

Tribological Properties of PM Cu-Based Dry Friction Clutch

2013 ◽  
Vol 545 ◽  
pp. 163-170 ◽  
Author(s):  
Jirapat Prapai ◽  
Monnapas Morakotjinda ◽  
Thanyaporn Yotkaew ◽  
Bhanu Vetayanukul ◽  
Ruangdaj Tongsri ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Dry Friction ◽  
Sintered Density ◽  
Sintering Temperature ◽  
Chemical Compositions ◽  
Friction Clutch ◽  
Frictional Materials ◽  
Dry Friction Clutch

Sintered Cu-based frictional materials were developed by using powder metallurgy (PM) method. The materials are aimed for application in a passenger car as a dry friction clutch. Effects of sintering temperature and composition on mechanical and tribological properties were determined. It was found that improper frictional material formulations caused inferior properties, particularly when the sintering temperatures were increased. Admixing of high Sn content (8 wt. %) resulted in decreases of sintered density and hardness with increasing sintering temperature. High Sn contents caused swelling of the sintered materials. Tribological properties (friction coefficient and wear rate) of the sintered specimens of the investigated materials were insensitive to sintering temperatures in the range of 800-950 °C but they were strongly influenced by chemical compositions. Addition of 3 wt. % graphite lowered the friction coefficient, which subsequently lowered the wear rate of the sintered material. To increase friction coefficient, one of the crucial properties of the dry friction clutch, of the sintered Cu-based frictional materials, two approaches were employed. In the first approach, substitution of graphite by SiO2 powders could improve the material friction coefficient. In the second approach, decreases of graphite content from 3 to 1 wt. % and of Sn content from 8 to 2 wt. % were conducted. The latter approach not only improved friction coefficient but also improved sintered density and hardness of the Cu-based frictional materials.

scholarly journals Molecular dynamics simulation to enhance the mechanical and tribological properties of polyimide composites by graphene reinforcement

2021 ◽  
Vol 2083 (2) ◽  
pp. 022107
Author(s):  
Zhe Chen ◽  
Aijiao Li ◽  
Hong Liu
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Polymer Composites ◽  
Tribological Properties ◽  
Friction And Wear ◽  
Dynamics Simulation ◽  
Mechanical And Tribological Properties

Abstract Background: Polyimide is one of the organic polymer materials with the best comprehensive performance. It has outstanding mechanical properties, excellent thermal stability and excellent corrosion resistance, but pure polyimide has high coefficient of friction and wear rate. By combining graphene with polyimide, the mechanical properties of the composite are significantly reformatived, and the friction coefficient and wear rate can be reduced. Objective: The molecular models were developed to study the mechanical and tribological properties of graphene as a reinforced material. Methods: In this paper, the mechanical properties and friction and wear mechanism of materials are studied by molecular dynamics method from the microscopic point of view. The Young’s modulus and hardness of composites were calculated using the strain constant method. Results: Molecular dynamics simulation results expressed that the Young’s modulus and hardness of polymer composites benefited by approximately 115% and 42%, respectively, after the addition of the graphene-reinforced material. The average friction coefficient and wear rate of polymer composites fall by 35% and 48%, respectively. Through the calculation and statistics of the micro-information in the process of friction simulation, the internal mechanism of various situations is revealed in the atomic dimension. Conclusions: Graphene can adsorb on the surface of polymer chain segment, a strong polymer matrix, through van der Waals and electrostatic forces and can effectively resist external loading.

Experimental study on the effect of surface texture on tribological properties of nanodiamond films under water lubrication

2021 ◽  
pp. 135065012110334
Author(s):  
Ying Yan ◽  
Xuelin Lei ◽  
Yun He
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Surface Texture ◽  
Diamond Film ◽  
Diamond Films ◽  
Nanocrystalline Diamond ◽  
Water Contact ◽  
Texture Density ◽  
Short Run

The effect of nanoscale surface texture on the frictional and wear performances of nanocrystalline diamond films under water-lubricating conditions were comparatively investigated using a reciprocating ball-on-flat tribometer. Although the untreated nanocrystalline diamond film shows a stable frictional state with an average friction coefficient of 0.26, the subsequent textured films show a beneficial effect on rapidly reducing the friction coefficient, which decreased to a stable value of 0.1. Furthermore, compared with the nanocrystalline diamond coating, the textured films showed a large decreasing rate of the corresponding ball wear rate from 4.16 × 10−3 to 1.15 × 10−3 mm3/N/m. This is due to the fact that the hydrodynamic fluid film composed of water and debris can provide a good lubrication environment, so the entire friction process has reached the state of fluid lubrication. Meanwhile, the surface texture can greatly improve the hydrophilicity of the diamond films, and as the texture density increases, the water contact angle decreases from 94.75° of the nanocrystalline diamond film to 78.5° of the textured films. The proper textured diamond film (NCD90) exhibits superior tribological properties among all tested diamond films, such as short run-in period, low coefficient of friction, and wear rate.

Tribological properties of the epoxy resin-based solid lubricant coating modified by Kevlar fibers

2018 ◽  
Vol 70 (9) ◽  
pp. 1706-1713 ◽  
Author(s):  
Guotao Zhang ◽  
Yanguo Yin ◽  
Ting Xie ◽  
Dan Li ◽  
Ming Xu ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Epoxy Resin ◽  
Tribological Properties ◽  
Dry Friction ◽  
Friction And Wear ◽  
Solid Lubricant ◽  
Transfer Film ◽  
Wear Properties ◽  
Content Type ◽  
Friction And Wear Properties

Purpose This paper aims to obtain high mechanical and good tribological properties of epoxy resin-based coatings under dry friction conditions. Design/methodology/approach Bonded solid lubricant coatings containing Kevlar fibres were prepared by a spraying method. The friction and wear properties of the coatings were experimentally investigated with a face-to-face tribometre under dry friction conditions. Scanning electron microscopy, energy dispersive X-ray spectroscopy and 3D laser scanning technologies were used to characterise the tribological properties. The action mechanism of the Kevlar fibres on a solid lubricant transfer film was also analysed. Findings Adding Kevlar fibres can significantly improve the wear resistance of the coatings. When the Kevlar fibre content increases, the tribological properties of the coatings improve and then worsen. Superior properties are obtained with 0.03 g of Kevlar fibres. Appropriately increasing the load or speed is beneficial to the removal of the outer epoxy resin and the formation of a lubricant film. During friction, the solid lubricants wrapped in the epoxy resin accumulate on the surface to form a transfer film that shows a good self-lubricating performance. In the later friction stage, fatigue cracks occur on the solid lubricant film but cannot connect to one another because of the high wear resistance and the entanglement of the rod-like Kevlar fibres. Thus, no large-area film falls from the matrix, thereby ensuring the long-term functioning of solid lubricant coatings. Originality/value Epoxy resin-based solid lubricant coatings modified by Kevlar fibres were prepared, and their friction and wear properties were investigated. Their tribological mechanisms were also proposed. This work provided a basis for the analysis of the tribological properties and design of bonded solid lubricant coatings containing Kevlar fibres.

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