scholarly journals NOVEL NANOSIZED FRICTION MODIFIERS FOR ENGINE, GEARBOX AND ROLLING BEARINGS LUBRICANTS

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Adolfo Senatore ◽  
Maria Sarno ◽  
Paolo Ciambelli
Keyword(s):  
Graphene Oxide ◽  
Wide Spectrum ◽  
Frictional Coefficient ◽  
Mineral Oil ◽  
Friction Reduction ◽  
Antiwear Additives ◽  
Protective Film ◽  
Wear Properties ◽  
Rolling Bearings ◽  
Group I

In this paper the tribological performances of graphene oxide nanosheets in mineral oil under wide spectrum of conditions, from boundary and mixed lubrication to elastohydrodynamic regimes, are reported. Nanosheets of graphene oxide prepared by a modified Hummer method have been dispersed in Group I mineral oil. The formulated lubricant has been tested through a ball on disc setup tribometer to quantify the friction reduction with respect to the base mineral oil. The good friction and anti-wear properties of the graphene-oil mixture may possibly be attributed to the small structure of the nanosheets and their extremely thin laminated structure, which offer lower shear stress and prevent direct interaction between metal asperities in engine applications as well as gearbox environment. The results clearly prove that graphene platelets in oil easily form protective film to prevent the direct contact between steel surfaces and, thereby, improve the frictional behaviour of the base oil. This evidence is also related to the frictional coefficient trend in the boundary regime. Furthermore, hybrid organic–inorganic nanocomposites with different composition were successfully tested as antifriction and antiwear additives for grease lubricants as potential breakthrough media in rolling bearings applications.

scholarly journals Graphene Oxide Nanosheets as Effective Friction Modifier for Oil Lubricant: Materials, Methods, and Tribological Results

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Adolfo Senatore ◽  
Vincenzo D'Agostino ◽  
Vincenzo Petrone ◽  
Paolo Ciambelli ◽  
Maria Sarno
Keyword(s):  
Graphene Oxide ◽  
Wide Spectrum ◽  
Frictional Coefficient ◽  
Mineral Oil ◽  
Friction Reduction ◽  
Protective Film ◽  
Graphene Oxide Nanosheets ◽  
Tribological Behaviour ◽  
Friction Modifier ◽  
Base Oil

The tribological behaviour of graphene oxide nanosheets in mineral oil was investigated under a wide spectrum of conditions, from boundary and mixed lubrication to elastohydrodynamic regimes. A ball-on-disc setup tribometer has been used to verify the friction reduction due to nanosheets prepared by a modified Hummers method and dispersed in mineral oil. Their good friction and antiwear properties may possibly be attributed to their small structure and extremely thin laminated structure, which offer lower shear stress and prevent interaction between metal interfaces. Furthermore, the results clearly prove that graphene platelets in oil easily form protective film to prevent the direct contact between steel surfaces and, thereby, improve the frictional behaviour of the base oil. This evidence is also related to the frictional coefficient trend in boundary regime.

scholarly journals Tribological Behaviour of Graphene Nanoplatelets as Additive in Pongamia Oil

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 732
Author(s):  
Yeoh Jun Jie Jason ◽  
Heoy Geok How ◽  
Yew Heng Teoh ◽  
Farooq Sher ◽  
Hun Guan Chuah ◽  
...  
Keyword(s):  
Friction And Wear ◽  
Graphene Nanoplatelets ◽  
Friction Reduction ◽  
Engine Oil ◽  
Protective Film ◽  
Tribological Behaviour ◽  
Wear Reduction ◽  
Pongamia Oil ◽  
Interacting Surfaces ◽  
Worn Surface

This study investigated the tribological behaviour of Pongamia oil (PO) and 15W–40 mineral engine oil (MO) with and without the addition of graphene nanoplatelets (GNPs). The friction and wear characteristics were evaluated in four-ball anti-wear tests according to the ASTM D4172 standard. The morphology of worn surfaces and the lubrication mechanism of GNPs were investigated via SEM and EDS. This study also focuses on the tribological effect of GNP concentration at various concentrations. The addition of 0.05 wt % GNPs in PO and MO exhibits the lowest friction and wear with 17.5% and 12.24% friction reduction, respectively, and 11.96% and 5.14% wear reduction, respectively. Through SEM and EDS surface analysis, the surface enhancement on the worn surface by the polishing effect of GNPs was confirmed. The deposition of GNPs on the friction surface and the formation of a protective film prevent the interacting surfaces from rubbing, resulting in friction and wear reduction.

Effect of CeO2 addition on microstructure and tribological characteristics of laser cladded Cu10Al–MoS2 coating under oil lubrication

2021 ◽  
pp. 146442072110309
Author(s):  
Shao Lifan ◽  
Ge Yuan ◽  
Kong Dejun
Keyword(s):  
Abrasive Wear ◽  
Wear Mechanism ◽  
Mass Fraction ◽  
Friction Reduction ◽  
Depth Of Field ◽  
Oil Lubrication ◽  
Wear Properties ◽  
Fatigue Wear ◽  
Wear Rates ◽  
Mass Fractions

In order to improve the friction and wear properties of Cu10Al–MoS2 coating, the addition of CeO2 is one of the present research hot spots. In this work, Cu10Al–MoS2 coatings with different CeO2 mass fractions were successfully fabricated on Q235 steel using a laser cladding. The microstructure and phase compositions of obtained coatings were analyzed using an ultra-depth of field microscope and X-ray diffraction, respectively. The friction-wear test was carried out under oil lubrication using a ball-on-disk wear tester, and the effects of CeO2 mass fraction on the microstructure, hardness, and friction-wear properties were studied, and the wear mechanism was also discussed. The results show that the laser cladded Cu10Al–MoS2 coatings with the different CeO2 mass fractions were mainly composed of Cu9Al4, Cu, AlFe3, Ni, MoS2, and CeO2 phases. The Vickers-hardness (HV) of Cu10Al–8MoS2–3CeO2, Cu10Al–8MoS2–6CeO2, and Cu10Al–8MoS2–9CeO2 coatings was 418, 445, and 457 HV0.3, respectively, which indicates an increase in hardness with the increase of CeO2 mass fraction. The average coefficients of friction (COF) and wear rates decrease with the increase of CeO2 mass fraction, presenting the outstanding friction reduction and wear resistance performances. The wear mechanism of Cu10Al–MoS2 coatings is changed from abrasive wear with slight fatigue wear to abrasive wear with the increase of CeO2 mass fraction.

Tribological behavior of TiAl matrix self-lubricating composites reinforced by multilayer graphene

RSC Advances ◽  
2015 ◽  
Vol 5 (55) ◽  
pp. 44618-44625 ◽  
Author(s):  
Kang Yang ◽  
Xiaoliang Shi ◽  
Wenzheng Zhai ◽  
Long Chen ◽  
Ao Zhang ◽  
...  
Keyword(s):  
Elastic Deformation ◽  
Tribological Behavior ◽  
Friction Reduction ◽  
Von Mises Stress ◽  
Multilayer Graphene ◽  
Wear Properties ◽  
Von Mises ◽  
Self Lubricating Composites

Anti-friction film with friction-reduction and anti-wear properties is formed under elastic deformation at the von Mises stress of 917 MPa (at 12 N).

Synthesis and tribological study of core-shell Ag@polyaniline as lubricant additive in lithium-based complex grease

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yanqiu Xia ◽  
Chen Chen ◽  
Xin Feng ◽  
Zhengfeng Cao
Keyword(s):  
Photoelectron Spectroscopy ◽  
Fourier Transforms ◽  
Friction Pair ◽  
Lubricant Additive ◽  
Friction Reduction ◽  
Core Shell ◽  
Protective Film ◽  
Simple Method ◽  
Content Type ◽  
Lubrication Mechanisms

Purpose The purpose of this paper is to synthesize a kind of core-shell Ag@polyaniline (Ag@PAN) as a lubricant additive to improve the friction reduction and anti-wear abilities of lithium-based complex grease. Design/methodology/approach The core-shell Ag@PAN was prepared by a simple method and was introduced into the lithium-based complex grease. The typical properties of Ag@PAN were investigated by scanning electron microscopy (SEM), Fourier transforms infrared spectrometer and thermal gravimetric analyzer. The tribological properties were evaluated under different conditions. After the tribological test, the worn surface was analyzed by SEM and X-ray photoelectron spectroscopy to probe the lubrication mechanisms. Findings The prepared Ag@PAN could greatly improve the friction reduction and wear resistance of the friction pair under different conditions. The preferable tribological performances were mainly attributed to the synergism of various lubrication mechanisms including “mending effect,” “rolling effect” and lubricating protective film, and so on. Originality/value This study synthesizes a new kind of core-shell Ag@PAN as a lubricant additive, and it possesses preferable friction reduction and anti-wear abilities.

scholarly journals Effects of Reduced Graphene Oxide (rGO) at Different Concentrations on Tribological Properties of Liquid Base Lubricants

Lubricants ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 11 ◽  
Author(s):  
Jankhan Patel ◽  
Amirkianoosh Kiani
Keyword(s):  
Graphene Oxide ◽  
Physical Properties ◽  
Reduced Graphene Oxide ◽  
Tribological Properties ◽  
High Speed ◽  
Friction And Wear ◽  
Control Sample ◽  
Wear Properties ◽  
Reduced Graphene ◽  
Friction And Wear Properties

In this study, reduced graphene oxide (rGO) nano platelets were used as an additive to enhance friction and wear properties of oil-based lubricants by preparing three samples at 0.01% w/w, 0.05% w/w, and 0.1% w/w concentrations. To analyze the direct effect of rGO nano platelets on tribological properties, 99.9% pure oil was used as a liquid lubricant. A comparative tribological study was done by performing a ball-on-disk wear test in situ under harsh conditions, which was further analyzed using a non-contact 3D optical profilometer. Morphological evaluation of the scar was done using transmission and scanning electron microscopy (TEM, SEM) at micro and nano levels. The lubricants’ physical properties, such as viscosity and oxidation number, were evaluated and compared for all samples including pure oil (control sample) as per ASTM standards. Findings of all these tests show that adding rGO nano platelets at 0.05% w/w showed significant reduction in friction at high speed and in wear up to 51.85%, which is very promising for increasing the life span of moving surfaces in machinery. Oxidation and viscosity tests also proved that adding rGO nano platelets to all samples does not sacrifice the physical properties of the lubricant, while it improves friction and wear properties.

Urinary Claudin-1 Level as a Marker of Podocyte Injury in Patients with Proteinuria

QJM ◽  
2020 ◽  
Vol 113 (Supplement_1) ◽  
Author(s):  
M E Nasser ◽  
S M Shawky ◽  
E A M Sanad
Keyword(s):  
Wide Spectrum ◽  
Cell Junction ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Podocyte Injury ◽  
Group Iii ◽  
Group I ◽  
Significant Difference ◽  
Diaphragm Cell ◽  
Control Study

Abstract Background The biology of claudins is a rapidly evolving field, and many intriguing questions remain unanswered. Although it had been assumed that the reason there are ≥24 isoforms of claudin is that each one has distinct permeability properties. The nephron displays a wide spectrum of claudins, whose distribution varies in each tubular segment. In diabetic nephropathy and glomerulonephritis the gene expression of claudin-1, is markedly upregulated in the podocyte, accompanied by a tighter filtration slit diaphragm (cell-cell junction made by the glomerular podocytes) and the appearance of TJ-like structures between the foot processes causing further podocytes injury and proteinuria. Aim of the work to assess urinary claudin -1 level as a marker of podocyte injury in patients with proteinuria. Patients and Methods it is a case control study which was conducted upon 90 subjects who were divided into three groups: group I included 30 patients with type II DM, group II included 30 patients with glomerulonephritis and group III had 30 healthy subjects as controls. Urinary claudin-1 level was measured by Enzyme linked Immunosorbent Assay (ELISA) Results In this study, we found that urinary claudin-1 level was significantly higher in diabetics group and GN group than in control group. In comparison between GN group and diabetic group, we found that urinary claudin-1 level was higher in GN group than in diabetics group but with no statistically significant difference between the two groups. Conclusion urinary claudin-1 level was significantly higher in diabetics and GN group and has positive correlation with uACR. So it can be used as marker of podocytes injury and proteinuria

Friction Properties of Ni-P-SiC Composite Plating in Water

2019 ◽  
Vol 823 ◽  
pp. 117-122
Author(s):  
Norifumi Miyanaga ◽  
Jun Tomioka
Keyword(s):  
Wear Resistance ◽  
Composite Coating ◽  
Room Temperature ◽  
Frictional Coefficient ◽  
High Hardness ◽  
Wear Properties ◽  
Practical Applications ◽  
Composite Plating ◽  
Sic Particles ◽  
Plate Type

Electroless nickels have been used in practical applications as versatile materials for anti-wear. The wear resistance is well-improved as a composite coating by incorporating particles. Composite platting offers various mechanical and electoronic functions, depending on the combination of a material matrix and particles deposited. Among them Ni-P plating reinforced with SiC particles have been growing in importance owing to its high hardness and better anti-wear properties. In this study, a Ni-P-SiC/Ni-P-SiC system was evaluated using a ball-on-plate type reciprocating tester, and the results were compared with that of SiC/SiC system at room temperature. As the results, the Ni-P-SiC/Ni-P-SiC system with the surfaces where SiC particles were appeared in clumps had the low frictional coefficient around 0.1 even in water.

Pristine, Reduced, and Alkylated Graphene Oxide as Additives to Paraffin Grease for Enhancement of Tribological Properties

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Sooraj Singh Rawat ◽  
A. P. Harsha ◽  
O. P. Khatri ◽  
Rolf Wäsche
Keyword(s):  
Graphene Oxide ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Protective Film ◽  
Elemental Mapping ◽  
Graphene Oxides ◽  
Fiber Network ◽  
Maximum Reduction ◽  
Reduced Graphene ◽  
Minimum Resistance

Abstract Pristine, reduced, and alkylated graphene oxides are applied as lubricating additives in paraffin grease. It has revealed that their crystalline structure governs the tribological properties of grease for steel tribo-pair. The microstructural analyses of grease samples showed that a loose fiber network of soap in the presence of graphene-based additive allows their facile release for efficient lubrication. The surface analyses based on the microscopic and elemental mapping show the development of a graphene-derived protective film on the worn scars, which protected the tribo-surfaces and subsided the wear. The reduced graphene oxide (rGO) with the interlamellar distance of 0.35 nm in the (002) plane provided minimum resistance to shear and exhibited maximum reduction in coefficient of friction (COF) for the paraffin grease. The presence of oxygen functionalities in the basal of pristine and alkylated graphene oxide (GO) compromised the interlamellar shearing under tribo-stress; consequently, higher COF than that of rGO.

scholarly journals Tribology Properties of Synthesized Multiscale Lamellar WS2 and Their Synergistic Effect with Anti-Wear Agent ZDDP

2019 ◽  
Vol 10 (1) ◽  
pp. 115 ◽  
Author(s):  
Na Wu ◽  
Ningning Hu ◽  
Jinhe Wu ◽  
Gongbo Zhou
Keyword(s):  
Friction Coefficient ◽  
Synergistic Effect ◽  
Solid Phase ◽  
Friction Reduction ◽  
Lubricating Oil ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Wear Properties ◽  
Base Oil ◽  
Electron Probe Micro Analyzer

The microscale/nanoscale lamellar-structure WS2 particles with sizes of 2 µm and 500 nm were synthesized by solid-phase reaction method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The synergies between microscale/nanoscale WS2 particles and ZDDP as lubricating oil additives was evaluated by means of UMT-2 tribometer at room temperature. The wear scars were examined with SEM and electron-probe micro-analyzer (EPMA). The results show that the anti-wear properties were improved and the friction coefficient was greatly decreased with the simultaneous addition of WS2 particles and ZDDP, and the largest reduction of friction coefficient was 47.2% compared with that in base oil. Moreover, the presence of ZDDP additive in the lubricant further enhances the friction-reduction and anti-wear effect of microscale/nanoscale WS2. This confirms that there is a synergistic effect between WS2 particles and ZDDP.

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