scholarly journals Effect of Graphene Oxide and Graphite on Dry Sliding Wear Behavior of Polyester Composites

2018 ◽  
Vol 55 (1) ◽  
pp. 102-110 ◽  
Author(s):  
Marian Bastiurea ◽  
Dumitru Dima ◽  
Gabriel Andrei

Graphene oxide and graphite filled polyester composites were prepared by using conventional melt-mixing methods in order to improve tribological performance of polyester. It was investigated friction stability, microhardness, friction coefficient, and specific wear rate of the composites in details. It was found that the presence of graphite and graphene oxide influenced friction coefficient and wear rate of the composites. Graphene oxide decreased wear rate with increasing of test speed and graphite decreased wear rate for composite for all speeds. Tribological performance of the polyester/graphene composites is mainly attributed to bigger thermal conductivity for graphene, which can easily dissipate the heat which appears during the friction process at bigger forces. The positive influence of graphite on coefficient of friction (COF) of the composites is the result of the clivage of graphite layers during the loadings due to van der Waals weak bonds between the graphite layers.

2020 ◽  
Vol 1002 ◽  
pp. 151-160 ◽  
Author(s):  
Anmar D. Mahdi ◽  
Saif S. Irhayyim ◽  
Salah F. Abduljabbar

Al7075 hybrid nanocomposites considered one of the most material utilized in modern engineering applications that required a combination of superior properties such as lightweight, high strength, excellent corrosion resistance, and high thermal conductivity. In the current study, Al7075 – 5 vol % graphite self-lubricating composite was reinforced by 0, 1.5, 2.5, 3.5, and 4.5 vol % WO3 nanoparticles in order to study the microstructural, mechanical, and wear characteristics. The classical powder metallurgy route was employed to fabricate the hybrid nanocomposites specimens. The microstructural analysis of the nanocomposites was characterized by utilizing a Field Emission Scanning Electron Microscope (FESEM) and Energy-Dispersive X-ray (EDX) analyses. Mechanical properties such as micro-hardness and diametral compressive strength were studied. Dry sliding wear test was performed under the various loads of 10, 15, 20, and 25 N at a sliding distance and sliding speed of 1810 m and 1.5 m/s, respectively. Results have revealed that the microhardness and diametral compressive strength considerably improved by increasing the WO3 content until 3.5 vol % and then slightly decreased. Besides, both the values of the wear rate and friction coefficient gradually reduced by increment the reinforcement content up to 3.5 vol % and then suddenly increases for all the applied loads. Nevertheless, the wear rate and friction coefficient were correlated positively with the applied loads. From the results obtained, graphite as solid lubricating material with WO3 nanoparticles was successfully combined into the Al7075 alloy matrix. The optimum mechanical and wear performance of the hybrid nanocomposite were revealed at 3.5 vol % content of WO3 nanoparticles.


2016 ◽  
Vol 35 (5) ◽  
pp. 487-492
Author(s):  
Ahmet Karaaslan ◽  
Alptekin Kısasöz ◽  
Ş. Hakan Atapek ◽  
Kerem Altuğ Güler

AbstractThe wear behavior of cast A7075 and A7075/SAF 2205 composite material fabricated by vacuum-assisted investment flask casting was investigated under dry sliding condition. The wear tests were carried out using a “ball-on-disc” type tribometer. In the wear tests, 100Cr6 and ZrO2 balls were used as counterparts and the load, total distance and rotating speed were selected as 10 N, 100 m and 100 rpm, respectively. The results were evaluated using the friction coefficient–distance diagram, weight loss and wear rate. All worn surfaces were examined by scanning electron microscope and wear characteristics of the materials were discussed as a function of the microstructural features. It was concluded that composite material had lower friction coefficient, less weight loss and slower wear rate than that of cast material.


2015 ◽  
Vol 817 ◽  
pp. 661-666 ◽  
Author(s):  
Yuan Gao ◽  
Jin Chuan Jie ◽  
Peng Chao Zhang ◽  
Jian Zhang ◽  
Tong Min Wang ◽  
...  

The dry sliding wear behavior of Cu-Cr-Zr alloy prepared by electromagnetic horizontal continuous casting was investigated. The wear behavior of the studied alloy was discussed in terms of friction coefficient, mass loss/sliding, specific wear rate and wear mechanism. The results indicate that with the increasing normal load and sliding velocity, the friction coefficient of Cu-Cr-Zr alloy decreased monotonically, the mass loss/sliding and specific wear rate increased. By wear surface morphology and composition analysis, the wear mechanisms were discussed preliminary. Oxidation and abrasion mechanisms dominated at the lower sliding velocities and loads. Increasing loads and velocities led to a combination of oxidation and adhesion. Plastic deformation was dominant for the higher applied load and sliding velocities.


2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Vineet Tirth

AA2218–Al2O3(TiO2) composites are synthesized by stirring 2, 5, and 7 wt % of 1:2 mixture of Al2O3:TiO2 powders in molten AA2218 alloy. T61 heat-treated composites characterized for microstructure and hardness. Dry sliding wear tests conducted on pin-on-disk setup at available loads 4.91–13.24 N, sliding speed of 1.26 m/s up to sliding distance of 3770 m. Stir cast AA2218 alloy (unreinforced, 0 wt % composite) wears quickly by adhesion, following Archard's law. Aged alloy exhibits lesser wear rate than unaged (solutionized). Mathematical relationship between wear rate and load proposed for solutionized and peak aged alloy. Volume loss in wear increases linearly with sliding distance but drops with the increase in particle wt % at a given load, attributed to the increase in hardness due to matrix reinforcement. Minimum wear rate is recorded in 5 wt % composite due to increased particles retention, lesser porosity, and uniform particle distribution. In composites, wear phenomenon is complex, combination of adhesive and abrasive wear which includes the effect of shear rate, due to sliding action in composite, and abrasive effect (three body wear) of particles. General mathematical relationship for wear rate of T61 aged composite as a function of particle wt % load is suggested. Fe content on worn surface increases with the increase in particle content and counterface temperature increases with the increase in load. Coefficient of friction decreases with particle addition but increases in 7 wt % composite due to change in microstructure.


2016 ◽  
Vol 844 ◽  
pp. 133-140 ◽  
Author(s):  
Mariya R. Komissarova ◽  
Ilia G. Dyakov ◽  
Yurii P. Gladii

Microhardness, friction coefficient, and wear rate of carburized titanium alloy VT 20 are considered. An X-ray diffractometer, a scanning electron microscopy (SEM) used to characterize the phase composition of the modified layer and its surface morphology. A pin-on-disc tribometer was occupied to evaluate wear behavior of the treated titanium alloys. It is established that the friction coefficient decreases from 0.46 (untreated sample) to 0.15 for the sample carburized at 750 °C during 5 min. Therefore, the anode carburizing of titanium alloys results in the reducing of the wear rate by 2 orders.


2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Ashish Kumar Mishra ◽  
Ram Krishna Upadhyay ◽  
Arvind Kumar

Abstract Additive manufacturing (AM) has witnessed substantial growth in recent years due to its excellent manufacturing capabilities and innovative production methodologies. However, the mechanical suitability aspect in terms of material wear has not received much attention yet and needs rigorous assessment. This study investigates the wear anisotropy in an AlSi10Mg alloy sample fabricated by selective laser melting (SLM) technique. Different scanning strategies encompassing the island and the continuous scanning patterns were used in sample manufacturing. The effects of the scanning vector orientation, design pattern, and the island pattern size on the mechanical wear and wear anisotropy have been analyzed in detail. The study also focused upon a comparative investigation of the wear properties at the top and the side surfaces to understand the wear anisotropy in different directions. The samples are fabricated both by the fresh and the recycled powder and the role of powder state is described. The ball-on-disk test is performed to simulate the similar contact applications for marine/automotive components such as bearings. Bearing steel balls are used as a standard sliding counterpart material to investigate the wear properties. The wear microstructure is analyzed by scanning electron microscopy. Overall, the island strategy with 2 mm hatch style and 45 deg scan rotation have achieved better wear resistance and friction coefficient compared with the continuous hatch style. The wear behavior is found to be anisotropic. The Raman spectra validate the presence of silicon and carbon particles on the wear track, which have a significant effect on the tribological properties. The type of particles present in the sliding zone characterizes different wear stages. Wear mechanism is described by considering four parameters, namely, scan pattern, scan vector rotation, type of powder, and the wear measurement direction. Results show that the surface wear rate of samples made by the fresh powder is lower than the recycled powder. However, samples of the recycled powder have friction modifier characteristics. The best wear rate and friction coefficient values are obtained with the island strategy (2 mm hatch, 45 deg scan rotation) in the side plane and are 3.76 × 10−6 mm3/N m, 0.0781, respectively.


2011 ◽  
Vol 311-313 ◽  
pp. 92-95 ◽  
Author(s):  
Kui Chen ◽  
Tian Yun Zhang ◽  
Wei Wei

Polypropylene/organo-montmorillonite (PP/OMMT) composites were investigated by XRD. Friction and wear behaviors of this composites sliding against GCr15 stainless steel were examined on M-2000 text rig in a ring-on-block configuration. Worn surfaces of PP and its composites were analyzed by SEM. The result shows that PP macromolecule chains have intercalated into OMMT layers and form intercalated nanocomposites. With the increase of mass fraction of OMMT, both wear rate and friction coefficient of composites first decrease then rise. With the increase of load, from 150 N, 200 N to 250 N, wear rate of composites increases, while friction coefficient reduces. The wear mechanisms of composites are connected with the content of OMMT. Composites were dominated by adhesive wear, abrasive wear and adhesive wear accompanied by abrasive wear respectively with the increase of OMMT content.


2017 ◽  
Vol 52 (17) ◽  
pp. 2281-2288 ◽  
Author(s):  
S Sivakumar ◽  
S Senthil Kumaran ◽  
M Uthayakumar ◽  
A Daniel Das

The dry sliding wear behaviour of LM 24 aluminum alloy composites reinforced with garnet particles was evaluated. Stir casting technique was used to fabricate the composites. A pin-on-disc wear-testing machine was used to evaluate the wear rate, in which an EN 24 steel disc was used as the counterface. Results indicated that the wear rates of the composites were lower than that of the matrix alloy and further decreased with the increase in garnet content. However, in both unreinforced and reinforced composites, the wear rate increased with the increase in load and the sliding speed. Increase in the applied load increased the wear severity by changing the wear mechanism from abrasion to particle cracking-induced delamination wear. It was found that with the increase in garnet content, the wear resistance increased monotonically. The observations have been explained using scanning electron microscopy analysis of the worn surfaces and the subsurface of the composites. In this work, the most influencing input and output parameters have been performed and the process parameters have been prioritized using genetic algorithm. Genetic algorithm is used to optimize the most influencing input as well as output process parameters. The practical significance of applying genetic algorithm to dry sliding wear behavior process has been validated by means of computing the deviation between predicted and experimentally obtained wear behavior of metal matrix composite.


2011 ◽  
Vol 197-198 ◽  
pp. 1184-1187
Author(s):  
Jian Wei Sun ◽  
Li Qin Wang ◽  
Le Gu

The tribologcial performance of PTFE composites filled with different contents of spherical-graphite and Flake-graphite were comparatively evaluated on MM-200 test rig in block-on-ring configuration under dry condition. The microstructures of worn surfaces of PTFE composites were examined with SEM, and wear mechanisms was also analyzed. The changes of notched impact strength with the content changed were also considered. The results show that the tribological performance of spherical-graphite was better than flake-graphite with same weight filled: The friction coefficient of spherical-graphite, about 0.10~0.15, was under flake-graphite, about 0.12~0.18; the wear rate of spherical-graphite was lower than flake-graphite at each content. Notched impact strength of spherical-graphite was from 7.0kJ/m2 to 8.7 kJ/m2 with the content increased, while flake-graphite was fall rapidly from 8.5kJ/m2 to 3.0kJ/m2 with the content added more than 5wt. %.


Author(s):  
LiQin Wang ◽  
JianWei Sun ◽  
Le Gu

The tribological performance of Polyetherimide (PEI) composites filled with different Polytetrafluoroethylene (PTFE) content was comparatively evaluated on MM-200 test rig in block-on-ring configuration under dry friction condition. The microstructures of worn surfaces, fractured surfaces and wear mechanisms of the PEI composite were examined under scanning electron microscope (SEM). The variations of elastic modulus and surface hardness with variation in composition were also investigated. The results showed that under conditions of dry friction the PTFE can lower the friction coefficient and reduce wear of the PEI composites. When filled with 10 wt. % PTFE, the composite had the lowest wear rate. For PEI filled with 5wt. % PTFE the friction coefficient was about 0.3 and remained comparatively stable with increase of the PTFE content.


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