Investigation of friction and wear behavior of hydroxyl-functionalized graphene nanoplatelets filled elastomer nanocomposites

Author(s):  
Hasan Kasim ◽  
Adem Onat ◽  
Barış Engin ◽  
İsmail Saraç

The use of unfilled pure elastomer parts is limited in friction wheels, roller tires, sealing elements, and dynamic friction air suspension applications requiring high wear resistance. This study investigates the mechanical and tribological properties of new nanocomposites obtained by adding hydroxyl-functionalized graphene nanoplatelets at 1, 4, and 8 phr (parts per hundred rubber) ratios to the carbon black filled main rubber compound of sealing elements designed for axle hubs. The synergistic effect of nanofiller materials on the wear behavior of nanocomposites was tested with a block-on-ring wear tester under dry sliding conditions at 1000 rpm and 15 N normal load conditions. The worn surfaces were examined with scanning electron microscopy and circularly polarized light–differential interference contrast topology microscopy to reveal the wear mechanism. The addition of functionalized graphene nanoplatelets to the nanocomposite compound caused significant changes in tensile strength and elongation values by changing the cross-link density. The wear rate of nanocomposites prepared with graphene nanoplatelets at 1, 4, and 8 phr ratios was 11.15%, 25.24%, and 36.54% lower than the main rubber mixture used, respectively. While the hysteresis loss decreased by 14.83% at 1 phr, this value increased in other filler ratios. Significant differences in temperature change occurred as the amount of filler increased. After the test, the temperature values of nanocomposites with 1 and 4 phr filler ratios were between about 85–89°C, while it was measured as 99°C in nanocomposites with 8 phr filler ratios. It has been observed that the homogeneous distribution of two-dimensional carbon allotropes such as graphene nanoplatelet added to the rubber matrix at the optimum rate will improve tribological properties such as better surface lubrication, low wear rate, and low friction coefficient.

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1246
Author(s):  
Bo Mao ◽  
Shuangjie Chu ◽  
Shuyang Wang

Friction and wear performance of austenite stainless steels have been extensively studied and show a close relationship with the friction-induced martensitic transformation. However, how the grain size and associated friction-induced martensitic transformation behavior affect the tribological properties of austenite steels have not been systematically studied. In this work, dry sliding tests were performed on an AISI 304 stainless steel with a grain size ranging from 25 to 92 μm. The friction-induced surface morphology and microstructure evolution were characterized. Friction-induced martensitic transformation behavior, including martensite nucleation, martensite growth and martensite variant selection and its effect on the friction and wear behavior of the 304 stainless steel were analyzed. The results showed that both the surface coefficient of friction (COF) and the wear rate increase with the grain size. The COF was reduced three times and wear rate was reduced by 30% as the grain size decreased from 92 to 25 μm. A possible mechanism is proposed to account for the effect of grain size on the tribological behavior. It is discussed that austenite steel with refined grain size tends to suppress the amount of friction-induced martensitic transformed and significantly alleviates both the plowing and adhesive effect during dry sliding.


Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 889
Author(s):  
Yelong Xiao ◽  
Pingping Yao ◽  
Haibin Zhou ◽  
Zhongyi Zhang ◽  
Taimin Gong ◽  
...  

A sensitivity analysis of braking speed and normal load on tribological properties of copper metal matrix composites (Cu-MMCs) was investigated using a subscale dynamometer. The morphologies of the worn surface and subsurface were observed by a scanning electron microscope and 3D video microscope. The results indicated that temperatures on the Cu-MMC surface increased with increasing the braking speed and normal load. The average coefficient of friction gradually decreased as the braking speed or normal load increased, and a slight decrease in the wear rate with increasing the braking speed up to 17 m/s after which a clear increasing trend was observed. As the normal load increased from 612 N to 1836 N, the wear rate decreased firstly and then promptly decreased. The transition in wear mechanism of Cu-MMC significantly depended on braking speed and normal load.


Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1589 ◽  
Author(s):  
Mazin Tahir ◽  
Abdul Samad Mohammed ◽  
Umar Azam Muhammad

The effect of various operational factors, such as sliding speed, normal load and temperature on the tribological properties of Date palm fruit syrup (DPFS) as an environmentally friendly lubricant, is investigated. Ball-on-disc wear tests are conducted on mild steel samples in the presence of DPFS as a lubricant under different conditions and the coefficient of friction and wear rate are measured. Scanning electron microscopy, stylus profilometry, and Fourier transform infrared spectroscopy are used to evaluate the wear tracks to determine the underlying wear mechanisms. Results showed that DPFS has excellent tribological properties in terms of low friction and low wear rates making it a potential candidate to be used as a lubricant in tribological applications.


2016 ◽  
Vol 674 ◽  
pp. 239-243
Author(s):  
Gai Zhao ◽  
Qi Hua Wang ◽  
Irina Hussainova ◽  
Qing Jun Ding

Polyimide (PI) composites have been widely used in a space science due to extraordinary properties, such as excellent mechanical and electrical properties, good thermal stability and chemical inertness, as well as high wear resistance. However, atomic oxygen (AO), as one of the main radiated constituents in low earth orbit, had an important influence on the structrural and tribological properties of the polyimide matrix. To investigate the mechanism of AO erosion on polyimide, MoS2/Al2O3/PI composites were fabricated by means of a hot-press molding technique and irradiated by AO in a ground-based simulation system. The chemical composition change of the irradiated surface was examined by X-ray photoelectron spectroscopy (XPS). Then, the friction and sliding wear behavior against GCr15 steel balls were evaluated in a ground-based simulation facility using ball-on-disk tribology test rig. The worn morphologies and radiated surfaces of the materials were observed by Scanning electron microscope (SEM) to reveal the wear mechanism. Experimental analysis indicated that oxidation induced by AO irradiation and degradation of PI molecular chains on the composite’ surface results in change in chemical composition and formation of “carpet-like” structures. Affected layer, gradually formed during the process of irradiation, plays an important role for wear performance of the materials increasing friction coefficient and wear rate. Incorporation of Al2O3 nanofibers and MoS2 nanoparticles is shown to be favourable for AO resistance, which is helpful for improvement in wear resistance of the PI.


1985 ◽  
Vol 107 (4) ◽  
pp. 491-495 ◽  
Author(s):  
Y. C. Chiou ◽  
K. Kato ◽  
T. Kayaba

It is shown that the severe-mild wear transition and the wear rate of 0.45 percent carbon steel pair in dry friction is greatly influenced by the change of normal stiffness from 1 N/mm to 586000 N/mm in loading system. The wear rate increases with the increase of normal stiffness and the severe wear state is predominant under larger normal stiffness at low sliding velocity (0.25 m/s). However, the wear rate decreases with the increase of normal stiffness and the mild wear state is predominant under larger normal stiffness at high sliding velocity (1.57 m/s). This complicated wear behavior is explained by analyzing the effect of normal stiffness and normal load on wear rate-sliding velocity curve. It suggests that the increase of normal stiffness should physically mean the increase of normal load.


2017 ◽  
Vol 24 (Supp01) ◽  
pp. 1850005
Author(s):  
ŞERAFETTIN EKİNCİ

Wear and friction hold an important place in engineering. Currently, scientific societies are struggling to control wear by means of studies on lubricants. Boric acid constitutes an important alternative with its good tribological properties similar to MO2S and graphite alongside with low environmental impacts. Boric acid can be used as a solid lubricant itself whereas it can be added or blended into mineral oils in order to yield better mechanical and tribological properties such as low shear stress due to the lamellar structure and low friction, wear and surface roughness rates. In this study, distinguishing from the literature, boric acid addition effect considering the temperature was investigated for the conventional ranges of internal combustion engines. Surface roughness, wear and friction coefficient values were used in order to determine tribological properties of boric acid as an environmentally friendly additive and mineral oil mixture in the present study. Wear experiments were conducted with a ball on disc experimental setup immersed in an oil reservoir at room temperature, 50[Formula: see text]C and 80[Formula: see text]C. The evolution of both the friction coefficient and wear behavior was determined under 10[Formula: see text]N load, at 2[Formula: see text]m/s sliding velocity and a total sliding distance of 9000[Formula: see text]m. Surface roughness was determined using atomic-force microscopy (AFM). Wear rate was calculated utilizing scanning electron microscope (SEM) visuals and data. The test results showed that wear resistance increased as the temperature increased, and friction coefficient decreased due to the presence of boric acid additive.


Author(s):  
Gao Wen ◽  
Chongsheng Long ◽  
Tang Rui ◽  
Jiping Wang

Carbon fiber reinforced carbon-silicon carbide composites (C/C-SiC) were prepared by chemical volume infiltration (CVI) method and reaction melt infiltration (RMI) technique of silicon liquid to carbon reinforce carbon matrix composites. The friction and wear behaviors of C/C-SiC composites at various loads and sliding speeds were investigated by MRH-3 block-on-ring tribometer at room temperature under water lubricating conditions. Furthermore, the morphologies, phase of the worn surface and the debris were observed, examined and analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDAX) respectively. Experimental results showed that the C/C-SiC composites had a better wear resistence, and the friction coefficient under water lubricated conditions is about 0.02–0.06. The influence of sliding speed on the friction coefficients and the specific wear rate of C/C-SiC is more obvious than that of normal load when the load is less than 200N (inclueded200N). The friction coefficient and the specific wear rate of C/C-SiC decreased as the sliding velocity increased. At the sliding speed higher than 2m/s, the friction coefficient is less than 0.02. The specific wear rates is at a low level about (2×10−7mm3/Nm–5×10−8mm3/Nm).


2015 ◽  
Vol 787 ◽  
pp. 528-533
Author(s):  
M. Kalayarasan ◽  
V. Prabhu Raja ◽  
V. Nithin ◽  
S. Vivinkumar ◽  
M. Vishwaanth

Artificial hip joints have been implanted throughout the world into patients suffering from disabling hip joint disease, to restore their painless joint function. This means replacing the femoral head and acetabular socket with artificial prosthetic components. In order to obtain artificial implants with enhanced physical, chemical, mechanical, biological and tribological properties resulting in the accelerated self-adaptation of human body and long term performance, it is necessary to combine the advantages of materials with various properties; biocompatibility, bioactivity, excellent corrosion resistance, high fatigue and tensile strength, low modulus of elasticity, coefficient of friction, and high wear resistance. The present work focuses on investigating the wear rate of multi-layer coatings for different combinations in order to reduce the wear rate of the prosthesis. Three different combinations of multilayer coating were deposited by plasma arc spraying technique on titanium. It was found that the multi-layer coating consists of Alumina as a primary coating and Zirconia as the secondary coating provides lower wear rate and higher hardness compared to other combinations which would give optimal performance and thereby increasing its longevity.


Author(s):  
Sandeep Kumar Khatkar ◽  
Rajeev Verma ◽  
Suman Kant ◽  
Narendra Mohan Suri

This article statistically investigates the effect of various parameters such as material factors: silicon carbide (SiC) reinforcement, graphite (Gr) reinforcement and mechanical factors: normal load, sliding distance and speed on the sliding wear rate of vacuum stir cast self-lubricating AZ91D-SiC-Gr hybrid magnesium composites. The sliding wear tests have been performed on pin-on-disc tribometer at 10-50N loads, 1-3m/s sliding speed and 1000-2000m sliding distance. It has been examined that hybrid composites yielded improved wear resistance with reinforcement of SiC and solid lubricant graphite. ANOVA and signal-to-noise ratio investigation indicated that applied load was the most critical factor influencing the wear rate, followed by sliding distance. Further, the AZ91D/5SiC/5Gr hybrid composite has exhibited the best wear properties. From the SEM and EDS analysis of worn surfaces, delamination was confirmed as the dominant wear mechanism for AZ91D-SiC-Gr hybrid composites.


2020 ◽  
pp. 002199832097903
Author(s):  
Seçkin Martin ◽  
Sinan Kandemir ◽  
Maksim Antonov

In this study, graphene nanoplatelets (GNPs) with a thickness of 50-100 nm have been utilized to improve the mechanical and tribological properties of A360 alloy due to their extraordinary mechanical properties and solid lubricant nature. For the investigation of tribological properties, ball-on disc tests were carried out at various temperatures including room temperature (RT), 150 °C, and 300 °C. According to the hardness and ball-on-disc test results, the nanocomposite samples reinforced with GNPs exhibited improved hardness and wear resistance. The improvement in the wear behavior of nanocomposites was referred to the temporarily formed solid lubricant film of harder GNPs during the wear, and hence coefficient of friction (COF) and volume loss were considerably reduced. Abrasive-adhesive, oxidative, and mild-to-severe were found to be main wear mechanisms at RT, 150 °C, and 300 °C, respectively. Overall, the results show that the nanocomposites fabricated by casting method combined with mechanical stirring and ultrasonication have promising wear performance, especially at elevated temperatures. This may suggest that these developed materials could be potential candidates to be used in the engineering applications requiring high temperature wear performance.


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