scholarly journals Optimizing the Microstructure, Mechanical, and Tribological Properties of Si-DLC Coatings on NBR Rubber for Its Potential Applications

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 671
Author(s):  
Guangqiao Liu ◽  
Zedong Wen ◽  
Kui Chen ◽  
Limei Dong ◽  
Zhenlu Wang ◽  
...  

Si doped diamond-like carbon (Si-DLC) films were deposited on nitrile-butadiene rubber (NBR), and the effects of deposition parameters on the mechanical and tribological properties of an Si-DLC top layer on NBR were investigated. Then, the sample with the best performance is selected to investigate its tribological behaviors and mechanism under different contact loads. The results show that the growth rate and the doped Si content are also decreased with increasing the CH4 flow rate. The Si atom exists in the form of Si-C bonds at low CH4 flow rate (≤40 sccm) and Si-C + Si-O-C bonds at high CH4 flow rate (≥60 sccm). Furthermore, the sp3 content increases monotonously, while the hardness and H3/E2 ratio firstly decreases and then increases. As a result, the friction and wear behaviors are in line with the change trend of the hardness. The lowest friction coefficient (~0.19) and a slight wear were achieved for the Si-DLC3 film under the relatively high load of 3 N. The tribological results indicate that the friction coefficient and wear increase monotonously with the increase of load, which is mainly attributed to the brittle fragmentation of films at a higher load, and thus a high strength and super toughness DLC films should be needed. Furthermore, the friction and wear behaviors of samples depend critically on its surface topography, and the wear is lower when the friction direction is parallel to the stripes.

2021 ◽  
Vol 2083 (2) ◽  
pp. 022107
Author(s):  
Zhe Chen ◽  
Aijiao Li ◽  
Hong Liu

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.


Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1336
Author(s):  
Jorge Caessa ◽  
Todor Vuchkov ◽  
Talha Bin Yaqub ◽  
Albano Cavaleiro

Friction and wear contribute to high energetic losses that reduce the efficiency of mechanical systems. However, carbon alloyed transition metal dichalcogenide (TMD-C) coatings possess low friction coefficients in diverse environments and can self-adapt to various sliding conditions. Hence, in this investigation, a semi-industrial magnetron sputtering device, operated in direct current mode (DC), is utilized to deposit several molybdenum-selenium-carbon (Mo-Se-C) coatings with a carbon content up to 60 atomic % (at. %). Then, the carbon content influence on the final properties of the films is analysed using several structural, mechanical and tribological characterization techniques. With an increasing carbon content in the Mo-Se-C films, lower Se/Mo ratio, porosity and roughness appeared, while the hardness and compactness increased. Pin-on-disk (POD) experiments performed in humid air disclosed that the Mo-Se-C vs. nitrile butadiene rubber (NBR) friction is higher than Mo-Se-C vs. steel friction, and the coefficient of friction (CoF) is higher at 25 °C than at 200 °C, for both steel and NBR countersurfaces. In terms of wear, the Mo-Se-C coatings with 51 at. % C showed the lowest specific wear rates of all carbon content films when sliding against steel. The study shows the potential of TMD-based coatings for friction and wear reduction sliding against rubber.


2010 ◽  
Vol 654-656 ◽  
pp. 2763-2766 ◽  
Author(s):  
Li Wen Mu ◽  
Xin Feng ◽  
Yi Jun Shi ◽  
Huai Yuan Wang ◽  
Xiao Hua Lu

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.


2021 ◽  
pp. 36-40
Author(s):  
F.F. Yusubov

Tribotechnical indicators of environmentally friendly frictional composite materials with phenol-formaldehyde matrix are studied. Friction tests were carried out on a MMW-1 vertical tribometer according to the pin-on-disk scheme. Keywords: brake pads, composites, friction and wear, plasticizers, degradation, porosity. [email protected]


Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1854
Author(s):  
Fei-xia Zhang ◽  
Yan-qiu Chu ◽  
Chang-sheng Li

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.


2018 ◽  
Vol 31 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Yingshuang Shang ◽  
Xian Wu ◽  
Yifan Liu ◽  
Zilong Jiang ◽  
Zhaoyang Wang ◽  
...  

The high strength of multiwalled carbon nanotubes (MWCNTs) indicates promising properties for industry applications to reduce frictional coefficient and improve mechanical properties, yet few researches have referred to its structural morphology on the thermal, mechanical, and tribological properties of composites. In this work, three different lengths of MWCNTs were used to prepare polyether ether ketone (PEEK) composites and investigate the effect of structural morphology of MWCNTs on the thermal, mechanical, and tribological properties of composites. Different lengths of MWCNTs endowed PEEK composites with different thermal, mechanical, and tribological properties. On thermal and mechanical properties, the incorporation of 10–30 μm length of MWCNTs increased more the effectiveness on the crystallization rate, showing a higher crystallization temperature and the best mechanical properties of the PEEK composites. On tribological properties, approximately 50 μm MWCNTs can effectively decrease adhesive wear, which is a benefit of forming a thin transfer film, thereby effectively decreasing the coefficient of friction and improving the wear resistance.


2019 ◽  
Vol 32 (6) ◽  
pp. 645-654
Author(s):  
Xiaotao Qiu ◽  
Congli Fu ◽  
Aiqun Gu ◽  
Yang Gao ◽  
Xiuli Wang ◽  
...  

High-performance anti-wear polyetheretherketone/polytetrafluoroethylene (PEEK/PTFE) blends have drawn much attention over the past few years, owing to their wide range of potential applications. However, a convenient and effective method to prepare such blends with superior mechanical and tribological properties is still lacking. In this work, we propose a promising approach that uses melt-processable PTFE (MP PTFE), instead of conventional PTFE, to prepare anti-wear blends. MP PTFE, with melt flow abilities under appropriate conditions, can disperse homogeneously in PEEK, enhancing both the mechanical and tribological properties of the PEEK/PTFE blend. To prove this postulation, in this work, both MP PTFE and commercial PTFE were blended with PEEK, separately, and the effects of PTFE type and content on the tensile and tribological properties of the blends were studied. The results showed that, although the addition of commercial PTFE to PEEK could increase the wear resistance, it decreased the tensile strength of PEEK significantly. Compared to the blends with commercial PTFE, the blends with MP PTFE exhibited better tribological performance and higher tensile strength for PTFE content below 10 wt%. It was confirmed that the better dispersion of MP PTFE in PEEK endowed the blends with higher tensile strength. The surface analysis indicated that the MP PTFE could readily migrate to and enrich the surfaces of the blends. The relatively high PTFE content on the surface favored the formation of tribo-films, enhancing the tribological properties of the blends.


2013 ◽  
Vol 734-737 ◽  
pp. 2369-2372
Author(s):  
Lei Lei Gao ◽  
Jin Zhong Zhang

A commercial Mg alloy was prepared through equal channel angular extrusion (ECAE) process. The effect of ECAE on mechanical and tribological properties of the alloy was investigated. Experimental results showed that the hardness and strength of the alloy with ECAE were higher than that of the alloy without ECAE and increased with the increase pass number. The friction coefficient and wear resistance of the alloy after ECAE were significantly improved.


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