Effect of Temperature on Tribological Properties and Wear Mechanisms of NiAl Matrix Self-Lubricating Composites Containing Graphene Nanoplatelets

A Cr-free Ni-based self-lubricating composites with MoS2 and Ag as lubricants were fabricated by the powder metallurgy method. The microstructures were examined. The mechanical properties and tribological behaviors of the composites were evaluated from room temperature to 800 °C. The fractography was observed and the fracture mechanisms were analyzed. The morphologies and the phase compositions of worn surfaces were determined and the wear mechanisms were elaborated. The results indicate that MoS2 did not completely decompose after sintering, and the NiMoAl-MoS2-Ag composite has the best tribological properties (0.22, 1.68 × 10−5) at 800 °C. The main wear mechanisms are micro-ploughing and plastic deformation. The improvement of tribological properties was attributed to the formation of the lubricating film consisting of NiO, Mo oxides, various molybdates, and Ag particles. The reactions resulting in these compositions are proposed. The mechanical properties degrade with the rise of temperature and the addition of lubricants. Both NiMoAl and NiMoAlAg alloys exhibit micro-void accumulation fracture while the composites with MoS2 reveal intergranular fracture.

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Tribological properties of hexagonal boron nitride nanoparticles or graphene nanoplatelets blended with an ionic liquid as additives of an ester base oil

Lubrication Science ◽

10.1002/ls.1543 ◽

2021 ◽

Author(s):

José M. Liñeira del Río ◽

Enriqueta R. López ◽

David E. P. Gonçalves ◽

Jorge H. O. Seabra ◽

Josefa Fernández

Keyword(s):

Ionic Liquid ◽

Boron Nitride ◽

Tribological Properties ◽

Hexagonal Boron Nitride ◽

Graphene Nanoplatelets ◽

Base Oil ◽

Boron Nitride Nanoparticles ◽

Ester Base

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Comparison in Tribological Properties of YBa2Cu3OX/Ag and Bi2Sr2CaCu2OX/Ag Self-Lubricating Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.291-294.34 ◽

2011 ◽

Vol 291-294 ◽

pp. 34-40

Author(s):

Hua Tang ◽

Wen Jing Li ◽

Chang Sheng Li

Keyword(s):

Friction Coefficient ◽

Tribological Properties ◽

Room Temperature ◽

Superconducting Transition ◽

Friction Test ◽

Average Value ◽

Structure And Morphology ◽

Disk Friction ◽

Pin On Disk ◽

Self Lubricating Composites

The YBa2Cu3Ox/Ag and Bi2Sr2CaCu2Ox/Ag self-lubricating composites were prepared using powder metallurgic method. The crystal structure and morphology of the as-synthesized samples were characterized by XRD and SEM. The YBa2Cu3Ox/Ag and Bi2Sr2CaCu2Ox/Ag self-lubricating composites were found to compose of superconductor phase and Ag phase. The tribological properties from ultra-low temperature to room temperature of the composites were studied by pin-on-disk friction test. It was found that the friction coefficients of pure YBa2Cu3Ox(YBCO) and Bi2Sr2CaCu2Ox(BSCCO) were both dropped abruptly when the temperature cooled below the superconducting transition temperature. At room temperature, the friction coefficient of pure YBa2Cu3Oxis 0.68~0.95, when mixing 15wt% Ag, the friction coefficient of the sample decreased to the lowest value 0.11. The friction coefficient of pure Bi2Sr2CaCu2Ox is 0.15~0.17, When Ag content reach 10wt%, the coefficient was lowest (average value is 0.13). The addition of appropriate amount of Ag obviously improve the tribological property of YBCO, while only slightly meliorate that of BSCO. On the other hand, the YBCO/Ag composites exhibit better tribological properties than BSCCO/Ag composites at higher load under the same experimental condition.

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

Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications ◽

10.1177/14644207211061641 ◽

2021 ◽

pp. 146442072110616

Author(s):

Hasan Kasim ◽

Adem Onat ◽

Barış Engin ◽

İsmail Saraç

Keyword(s):

Wear Rate ◽

Tribological Properties ◽

Wear Behavior ◽

Normal Load ◽

Graphene Nanoplatelets ◽

Rubber Matrix ◽

High Wear Resistance ◽

Homogeneous Distribution ◽

Functionalized Graphene ◽

Sealing Elements

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.

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Effect of Temperature on the Tribological Properties of Selected Thermoplastic Materials Cooperating with Aluminium Alloy

Materials ◽

10.3390/ma14237318 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7318

Author(s):

Anita Ptak ◽

Paula Taciak ◽

Wojciech Wieleba

Keyword(s):

Aluminium Alloy ◽

Contact Pressure ◽

Tribological Properties ◽

Polymer Materials ◽

Effect Of Temperature ◽

Test Results ◽

Friction Process ◽

Before And After ◽

Pin On Disc ◽

Two Parameters

This article concerns the tribological properties of three selected polymer materials: polyamide PA6, polyethylene PE-HD and polyetheretherketone composite PEEK/BG during sliding against aluminium alloy EN AW-2017A in the presence of hydraulic oil HLP 68. The tests were carried out under contact pressure p of 3.5–11 MPa at ambient temperature T ranging from −20 °C to +20 °C. The dependence of kinetic friction coefficient μk on the two parameters was determined through tribological tests carried out using a pin-on-disc tribometer. A five-level central composite rotatable design (CCRD) was adopted for the experiment. All the test results were statistically analysed. The microhardness of the surface of the polymeric material was measured before and after the friction process. The surface was also examined under SEM. Temperature and contact pressure have been found to have a significant effect on the tribological properties of the tested sliding pairs. Relative to the applied friction conditions, the surfaces after friction showed rather heavy signs of wear.

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Improvement in Tribological Properties of Cr12MoV Cold Work Die Steel by HVOF Sprayed WC-CoCr Cermet Coatings

Coatings ◽

10.3390/coatings9120825 ◽

2019 ◽

Vol 9 (12) ◽

pp. 825 ◽

Cited By ~ 5

Author(s):

Sheng Hong ◽

Yuping Wu ◽

Bo Wang ◽

Jinran Lin

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Tribological Properties ◽

Sliding Wear ◽

Cold Work ◽

Environmental Scanning Electron Microscopy ◽

Effect Of Temperature ◽

Die Steel ◽

Die Steels ◽

Scanning Electron

The main objective of this study was to develop an efficient coating to increase the wear resistance of cold work die steel at different temperatures. The microstructures of high-velocity oxygen-fuel (HVOF)-sprayed WC-CoCr coatings were evaluated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of temperature on the tribological properties of the coatings and the reference Cr12MoV cold work die steel were both investigated by SEM, environmental scanning electron microscopy (ESEM), X-ray diffraction (XRD), and a pin-on-disk high-temperature tribometer. The coating exhibited a significantly lower wear rate and superior resistance against sliding wear as compared to the die steel at each test temperature, whereas no major differences in terms of the variation tendency of the friction coefficient as a function of temperature were observed in both the coatings and the die steels. These can be attributed to the presence of nanocrystalline grains and the fcc-Co phase in the coating. Moreover, the wear mechanisms of the coatings and the die steels were compared and discussed. The coating presented herein provided a competitive approach to improve the sliding wear performance of cold work die steel.

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