scholarly journals Reduction of the Coefficient of Friction of Steel-Steel Tribological Contacts by Novel Graphene-Deep Eutectic Solvents (DESs) Lubricants

Lubricants ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 37 ◽  
Author(s):  
Ignacio Garcia ◽  
Silvia Guerra ◽  
Juan de Damborenea ◽  
Ana Conde
Keyword(s):  
Mechanical Properties ◽  
Ionic Liquids ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Adhesive Wear ◽  
Choline Chloride ◽  
Deep Eutectic Solvents ◽  
The Other ◽  
Graphene Flakes ◽  
The Coefficient Of Friction

Deep eutectic ionic liquids (DES) possess similar properties to conventional ionic liquids (ILs). However, ILs cannot be considered as environmentally friendly compounds due to both its processing and synthesis, which could have significant polluting effects. On the contrary, deep eutectic solvents (DESs) can be biodegradable, non-toxic, and have a lower price than most ILs, making them potentially useful in a wide variety of advanced technological applications, such as tribology. On the other hand, graphene has recently been proposed as an extremely promising lubricant due to its combination of mechanical properties and chemical stability as well as its “green” character. In the present paper, graphene flakes (≈250 nm) have been used as an additive to DES composed of choline chloride (ChCl)-urea, ChCl-ethylene glycol, and ChCl-malic acid. According to the results, the addition of 1 wt% graphene reduces friction coefficient (COF) and, notably, prevents adhesive wear, reducing wear rate on steel-steel sliding contacts.

Effect of Tempering on the Wear Characteristics of Induction-Hardened SPS5 Steel

2007 ◽  
Vol 353-358 ◽  
pp. 835-839
Author(s):  
M.H. Kim ◽  
Kyong Yop Rhee ◽  
Jai Sung Hong ◽  
Young Sam Ham
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Adhesive Wear ◽  
Real Contact Area ◽  
Wear Particles ◽  
Wear Characteristics ◽  
Real Contact ◽  
Heat Treated ◽  
The Coefficient Of Friction ◽  
Wear Tests

In this study, the tempering effect on the wear characteristics of induction-hardened SPS5 steel was investigated. For this purpose, three tempering conditions were applied to control the hardness and microstructure of heat-treated SPS5 steel. Ball-on-disk wear tests have been performed using zircornia balls on the tempered specimens to determine the variation of wear characteristics. The results showed that friction coefficient decreased with increasing hardness for induction-hardened SPS5 steel. This seems to occur because real contact area between specimen and mating ball was affected by the specimen hardness. Also, we observe the wear type changes from the plowing wear to the adhesive wear as the hardness increases and the adhesive wear particles act as an obstacle to the transmission of the force of friction, reducing the coefficient of friction and the wear rate.

scholarly journals A Review of the electrochemical corrosion of metals in choline chloride based deep eutectic solvents

2021 ◽  
Author(s):  
Mihael Bučko ◽  
Jelena Bajat
Keyword(s):  
Ionic Liquids ◽  
Corrosion Rate ◽  
Wide Spectrum ◽  
Choline Chloride ◽  
Electrochemical Corrosion ◽  
Deep Eutectic Solvents ◽  
High Viscosity ◽  
Metal Corrosion ◽  
Melting Points ◽  
Separate Class

Deep eutectic solvents (DESs) are a class of mixtures with melting points notably lower than those of their raw constituent components. These liquids have found a tremendously wide spectrum of applications in the last two decades of their research, so their contact and interaction with technical metals and alloys are inevitable. Therefore, the corrosivity of DESs towards metals is an extremely important topic. This review summarizes research efforts collected in the last two decades related to the corrosion rate of various metals in different DESs. Since the DESs are mainly composed of organic raw compounds, and by their physicochemical properties they may be regarded as a separate class of ionic liquids, the literature data about DESs corrosivity has been compared to the data related to the corrosivity of various organic solvents and ionic liquids as well. All the results gained until now show significantly low corrosivity of DESs. This observation is discussed in relation to the chemical composition of DESs. The absence of the oxidizing agents, the inhibitory action of organic ions and molecules, high viscosity and low electrical conductivity have been recognized as the main factors contributing to the low metal corrosion rate in DESs.

Tribological Properties of Polyoxymethylene Composites Against Aluminum

2003 ◽  
Vol 125 (3) ◽  
pp. 661-669 ◽  
Author(s):  
Masaya Kurokawa ◽  
Yoshitaka Uchiyama ◽  
Tomoaki Iwai ◽  
Susumu Nagai
Keyword(s):  
Wear Rate ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
High Surface ◽  
Surface Hardness ◽  
Disk Surface ◽  
Optical Microscope ◽  
Transfer Film ◽  
The Other ◽  
The Coefficient Of Friction

Tribological properties of several kinds of polyoxymethylene (POM) composites were evaluated for the purpose of developing a polymeric tribomaterial especially suited for mating with aluminum parts having low surface hardness. POM composites containing small amounts of silicon carbide (SiC), POM/SiC; those containing a small amount of calcium octacosanonoate besides SiC, POM/SiC/Ca-OCA; and the one blended with 24 wt % of polytetrafluoroethylene, POM/PTFE(24); were injection-molded into pin specimens and their tribological properties were tested by means of a pin-on-disk type wear apparatus using an aluminum (A5056) mating disk in comparison with a 303 stainless steel (SUS303) disk. Evaluation was focused on observation of the sliding surfaces of the pin specimens and the mating disks by a scanning electron microscope and an optical microscope together with the measurement of surface roughness. In the case of mating against a SUS303 disk having high surface hardness, all pin specimens did not roughen the disk surfaces even after long time of rubbing. Only POM/PTFE(24) composite obviously made a transfer film on the disk surface, while the other composites made an extremely thin one on it. POM/SiC(0.1)/Ca-OCA(1) composite, containing SiC 0.1 wt. % and Ca-OCA 1 wt. %, was found to show the lowest coefficient of friction and the lowest wear rate forming extremely thin transfer film on the mating disk. On the other hand, against an A5056 disk which has lower surface hardness than that of SUS303 disk, unfilled POM and POM composites except POM/SiC(0.1)/Ca-OCA(1) composite roughened the disk surfaces. However, the sliding surface of the A5056 disk rubbed with POM/SiC(0.1)/Ca-OCA(1) composite was significantly smoother and that of the pin specimen was also quite smooth in comparison with other pin specimens. Further, when each POM composite was rubbed against the A5056 disk, formation of transfer film was not obvious on the disk surfaces. For POM/SiC(0.1)/Ca-OCA(1) composite, the wear rate was the lowest of all POM composites, and the coefficient of friction was as low level as 60 percent of that of unfilled POM, but slightly higher than that of POM/PTFE(24) composite. For POM/SiC(0.1)/Ca-OCA(1) composite, the nucleating effect of SiC and Ca-OCA, which accelerated the crystallization of POM during its injection molding to form a matrix containing fine spherulites, must have resulted in increasing the toughness of the matrix and lowering the wear rate. Also, the lubricant effect of Ca-OCA should have lowered the coefficient of friction of the same matrix for rubbing against aluminum mating disk. POM/SiC(0.1)/Ca-OCA(1) composite was concluded as an excellent tribomaterial for mating with aluminum parts.

Effects of potassium titanate whisker and glass fiber on tribological and mechanical properties of PTFE/PEEK blend

2017 ◽  
Vol 30 (6) ◽  
pp. 752-764 ◽  
Author(s):  
Xue Teng ◽  
Lefei Wen ◽  
Yunxia Lv ◽  
Wenge Tang ◽  
Xiaogang Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Glass Fiber ◽  
Tribological Properties ◽  
Reinforcing Effect ◽  
Potassium Titanate ◽  
Polyether Ether Ketone ◽  
Ether Ketone

Two series of 10% polytetrafluoroethylene (PTFE)/polyether ether ketone (PEEK) composites reinforced with potassium titanate whisker (PTW/PTFE/PEEK) and chopped glass fiber (GF/PTFE/PEEK) were prepared and characterized. We investigated the effects of the additives on thermal stability, tribological properties, mechanical properties, and rheological behavior. The results illustrated that the mechanical properties of 10% PTFE/PEEK blend can be dramatically improved by incorporating either PTW or GF; however, the reinforcing effect of GF was found to be superior. It was found that 1% additive resulted in blends with the best tribological properties. Compared to the unmodified blend, the friction coefficient and wear rate of the 1% PTW blend decreased by 7.2% and 21%, respectively, while the corresponding values of 1% GF blend decreased by 0.66% and 51%, respectively.

scholarly journals Microstructure, and Mechanical and Wear Properties of Grp/AZ91 Magnesium Matrix Composites

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1190 ◽  
Author(s):  
Chang-rui Wang ◽  
Kun-kun Deng ◽  
Yan Bai
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Yield Strength ◽  
Wear Mechanism ◽  
Thermal Deformation ◽  
Volume Fraction ◽  
Az91 Alloy

Based on semi-solid mixing technology, two kinds of as-cast Grp (Graphite particles)/AZ91 composites with different Grp volume fractions (5 vol %, 10 vol %) were prepared; these are called 5 vol % Grp/AZ91 composites and 10 vol % Grp/AZ91 composites, respectively. In order to eliminate casting defects, refine grains, and improve mechanical properties, thermal deformation analysis of these composites was conducted. The effect of the addition of Grp and thermal deformation on the microstructure, mechanical properties, and wear resistance of AZ91 composite was explored. The results showed that after 5 vol % Grp was added into the as-cast AZ91 alloy, Mg17Al12 phases were no longer precipitated reticularly along the grain boundary, and Al4C3 phases were formed inside the composite. With the increase in the volume fraction of Grp, the grains of the AZ91 composites were steadily refined. With the increase of forging pass, the grain size of 5% Grp/AZ91 composites decreased first, and then increased. Additionally, the Grp size decreased gradually. There was little change in the yield strength, and the tensile strength and elongation were improved to a certain extent. After forging and extrusion of 5% Grp/AZ91 composites once, the grain size and Grp size were further reduced, and the yield strength, tensile strength, and elongation were increased by 23%, 30%, and 65%, respectively, compared with the composite after forging. With the increase of the number of forging passes before extrusion, the grain size decreased little by little, while the Grp size remained unchanged. The average yield strength, tensile strength, and elongation of the composites after forging and extrusion six times were increased by 3%, 3%, and 23%, respectively, compared with the composite after forging and extrusion once. The wear rate and friction coefficient of the 5% Grp/AZ91 composites decreased after forging once, and the wear mechanism was mainly due to ploughing wear. By comparison, the wear rate and friction coefficient of the 5% Grp/AZ91 composites increased in the extrusion state, and the main wear mechanism was from wedge formation and micro-cutting wear.

Friction and Wear Behavior of Polypropylene/Montmorillonite Intercalated Nanocomposites

2011 ◽  
Vol 311-313 ◽  
pp. 92-95 ◽  
Author(s):  
Kui Chen ◽  
Tian Yun Zhang ◽  
Wei Wei
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Abrasive Wear ◽  
Wear Mechanisms ◽  
Mass Fraction ◽  
Friction And Wear ◽  
Adhesive Wear ◽  
Wear Behavior ◽  
Friction And Wear Behavior

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.

ADHESIVE WEAR AND FRICTIONAL BEHAVIOR OF MULTILAYERED POLYESTER COMPOSITE BASED ON BETELNUT FIBER MATS UNDER WET CONTACT CONDITIONS

2009 ◽  
Vol 16 (03) ◽  
pp. 407-414 ◽  
Author(s):  
B. F. YOUSIF ◽  
ALVIN DEVADAS ◽  
TALAL F. YUSAF
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Adhesive Wear ◽  
Specific Wear Rate ◽  
Wear Performance ◽  
Fiber Mats ◽  
Polyester Composite ◽  
Sliding Distance ◽  
Wet Contact

In the current study, a multilayered polyester composite based on betelnut fiber mats is fabricated. The adhesive wear and frictional performance of the composite was studied against a smooth stainless steel at different sliding distances (0–6.72 km) and applied loads (20–200 N) at 2.8 m/s sliding velocity. Variations in specific wear rate and friction coefficient were evaluated at two different orientations of fiber mat; namely parallel (P–O) and normal (N–O). Results obtained were presented against sliding distance. The worn surfaces of the composite were studied using an optical microscope. The effect of the composite sliding on the stainless steel counterface roughness was investigated. The results revealed that the wear performance of betelnut fiber reinforced polyester (BFRP) composite under wet contact condition was highly dependent on test parameters and fiber mat orientation. The specific wear rate performance for each orientation showed an inverse relationship to sliding distance. BFRP composite in N–O exhibited better wear performance compared with P–O. However, the friction coefficient in N–O was higher than that in P–O at lower range of applied load. The predominant wear mechanism was debonding of fiber with no pullout or ploughing. Moreover, at higher applied loads, micro- and macrocracking and fracture were observed in the resinous region.

scholarly journals Review on Carbon Dioxide Absorption by Choline Chloride/Urea Deep Eutectic Solvents

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Rima J. Isaifan ◽  
Abdukarem Amhamed
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Bond ◽  
Ionic Liquids ◽  
Choline Chloride ◽  
Deep Eutectic Solvents ◽  
Absorption Capacity ◽  
Carbon Dioxide Absorption ◽  
Hydrogen Bond Donor ◽  
Separation Processes ◽  
Hydrogen Bond Acceptor

In the recent past few years, deep eutectic solvents (DESs) were developed sharing similar characteristics to ionic liquids but with more advantageous features related to preparation cost, environmental impact, and efficiency for gas separation processes. Amongst many combinations of DES solvents that have been prepared, reline (choline chloride as the hydrogen bond acceptor mixed with urea as the hydrogen bond donor) was the first DES synthesized and is still the one with the lowest melting point. Choline chloride/urea DES has proven to be a promising solvent as an efficient medium for carbon dioxide capture when compared with amine alone or ionic liquids under the same conditions. This review sheds light on the preparation method, physical and chemical characteristics, and the CO2 absorption capacity of choline chloride/urea DES under different temperatures and pressures reported up to date.

Some Physical and Mechanical Properties of Garlic

2007 ◽  
Vol 3 (6) ◽  
Author(s):  
Adel H. Bahnasawy
Keyword(s):  
Mechanical Properties ◽  
Friction Coefficient ◽  
Contact Surface ◽  
Chemical Properties ◽  
Physical And Mechanical Properties ◽  
Friction Angle ◽  
Arithmetic Mean ◽  
The Other ◽  
Cross Sectional ◽  
Length Width

The physical parameter results showed that the garlic geometric and arithmetic mean diameters ranged from 2.53 to 4.93, and 2.53 to 5.02 cm, respectively according to the bulb size categories. The cloves' length, width and thickness were 1.92 to 2.91, 0.78 to 1.32, and 0.69 to 0.99 cm, respectively. The surface and cross-sectional of areas ranged from 53.31 to 136.4 and 29.1 to 128.4 cm2, respectively. The number of cloves ranged from 18 to 51/bulb according to the bulbs size categories. Bulk density, repose angle and coefficient of contact surface values ranged from 892 to 1007 kg/m3, 41.52 to 45.04º, and 0.91 to 1.12, respectively, according to the bulb size categories.The chemical properties showed that the emptying (friction) angle ranged from 23.25 to 28.82º, where small bulbs recorded the highest values on the concrete surfaces, while the lowest values were recorded by the large bulbs on the iron surfaces. The friction coefficient decreased with increasing bulb size, where it was the highest (0.8) for the small bulbs on the concrete surfaces; on the other hand, the lowest values (0.36) were recorded for the large bulbs on the iron surfaces. The crushing load of the cloves ranged from 55.6 to 155.0 N, depending on the bulb size. The force required for loosening the cloves from the bulb ranged from 110 to 272 and 101 to 320 N on the horizontal and vertical positions of the bulbs.

Tribological Investigations of Parts Sintered and Coated by Laser Beam

2005 ◽  
Vol 473-474 ◽  
pp. 255-260 ◽  
Author(s):  
T. Sebestyén ◽  
Gábor Buza ◽  
F. Franek ◽  
János Takács ◽  
Zoltán Kálazi ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Steel Substrate ◽  
Laboratory Model ◽  
Reinforced Polymers ◽  
The Coefficient Of Friction ◽  
Glass Fibre Reinforced ◽  
Pin On Disk ◽  
Short Carbon

In this work we intend to investigate the surface properties of laser sintered and coated parts, by measurement of friction coefficient and wear rate. The main aim of this research is to justify laser sintered prototype tools for injection molding of fibre-reinforced polymers. For increase of wear resistance we used hard Co-based and Fe-based coatings on laser-sintered phosphorous bronze and unalloyed steel substrate. Short carbon- and glass-fibre-reinforced polymers were used as counter bodies. For the tribological laboratory model tests a pin-on-disk test rig was used. In case of coated parts – with higher wear resistance – we used a cylinder-on-cylinder tribometer. The tribological properties were determined at different load conditions. Our results show that the friction coefficient and wear resistance of laser treated surfaces are good. The coefficient of friction of coated specimens is slightly less, but the wear rate is significantly less.

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