Molecular dynamics study on the mechanical and tribological properties of polyimide reinforced by lanthana

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Peng Cai ◽  
Chengpeng Xu ◽  
Fei Zheng ◽  
Jingfu Song ◽  
Gai Zhao
Keyword(s):  
Tribological Properties ◽  
Design Methodology ◽  
Friction And Wear ◽  
Relative Concentration ◽  
Rare Earth Oxide ◽  
Dynamic Simulations ◽  
Adsorption Effect ◽  
Content Type ◽  
Mechanical And Tribological Properties ◽  
Frictional Interface

Purpose The purpose of this paper is to investigate the effect of lanthana (La2O3) on the mechanical and tribological properties of polyimide (PI). Design/methodology/approach The mechanical and tribological properties of PI nanocomposites filled with La2O3 were studied by molecular dynamic simulations to explore the deep mechanisms from an atomic or molecular view. Findings The results showed that the hardness of the PI matrix increased after La2O3 modification with a decrease of 72.4% nanoindentation depth. Besides, the friction coefficient of PI decreased by 72.2% after filling La2O3, and the shear deformation was largely reduced under the same conditions. The adsorption effect of La2O3 on the PI molecular, which reduced the atomic relative concentration, velocity, interaction with counterpart Fe layer and the temperature rise in the frictional interface, contributed to the improvement of the mechanical and tribological performance. Originality/value This study reveals the friction and wear mechanism of PI composites filled with rare earth oxide at the nanoscale.

Effect of rare earth oxide on the mechanical and tribological properties of polyimide nanocomposites

2020 ◽  
Vol 72 (3) ◽  
pp. 433-437
Author(s):  
Yuanhao Yu ◽  
Jingfu Song ◽  
Gai Zhao ◽  
Qingjun Ding
Keyword(s):  
Rare Earth ◽  
Tribological Properties ◽  
Design Methodology ◽  
Rare Earth Oxide ◽  
Hot Press ◽  
Content Type ◽  
Mechanical And Tribological Properties ◽  
Hot Press Sintering ◽  
The Impact ◽  
Weak Influence

Purpose This paper aims to study the effect of different rare earth oxide on the tribological properties of polyimide (PI) nanocomposites based on the CNT and GO reinforcements. Design/methodology/approach The PI nanocomposites filled with different rare earth oxide based on the carbon nanotubes and graphene oxide were designed and prepared by hot press sintering. The mechanical and tribological properties of PI nanocomposites were carried out, and their reinforcement mechanisms were discovered. Findings Rare earth oxide had a weak influence on the impact strength of PI nanocomposites. Filling La2O3 can dramatically reduce the friction coefficient and wear rate of PI nanocomposites. Originality/value The PI nanocomposites filled with rare earth oxide based on the CNT and GO reinforcements were designed, and their mechanical and tribological properties were studied.

The tribological performance of engineered micro-surface topography by picosecond laser on PEEK

2019 ◽  
Vol 72 (1) ◽  
pp. 172-179 ◽  
Author(s):  
Meiling Wang
Keyword(s):  
Tribological Properties ◽  
Design Methodology ◽  
Friction And Wear ◽  
Picosecond Laser ◽  
Wear Property ◽  
Content Type ◽  
Friction Curve ◽  
Micro Structures ◽  
Wear Tests ◽  
Friction And Wear Tests

Purpose The purpose of this study is to investigate the effect of engineered micro-structures on the tribological properties of metal-polyetheretherketone (PEEK) surface. Design/methodology/approach Circular dimples with diameters of 25 and 50 µm were designed and manufactured on PEEK plate specimens using picosecond laser. Reciprocating friction and wear tests on a ball-on-flat configuration were performed to evaluate the tribological properties of the designed micro-structures in dry contacts. The loading forces of 0.9 and 3 N were applied. Findings As a result, obvious fluctuations of coefficient of friction curve were observed in tribosystems consisting of non-textured and textured PEEK with circular dimples of 25 µm in diameter. GCr15 ball/textured PEEK plate specimens with circular dimples of 50 µm in diameter revealed a superior friction and wear property. Originality/value Different to the existing studies in which the tribopairs consist of hard bearing couples, this study investigated the tribological properties of the engineered micro-structures on the hard-on-soft bearing couples.

Influence of the particle size on the physical, mechanical and tribological properties of composites for brake pads

2021 ◽  
pp. 36-40
Author(s):  
F.F. Yusubov
Keyword(s):  
Particle Size ◽  
Composite Materials ◽  
Tribological Properties ◽  
Friction And Wear ◽  
Phenol Formaldehyde ◽  
Environmentally Friendly ◽  
Brake Pads ◽  
Mechanical And Tribological Properties ◽  
Pin On Disk ◽  
Properties Of Composites

Tribotechnical indicators of environmentally friendly frictional composite materials with phenol-formaldehyde matrix are studied. Friction tests were carried out on a MMW-1 vertical tribometer according to the pin-on-disk scheme. Keywords: brake pads, composites, friction and wear, plasticizers, degradation, porosity. [email protected]

Tribological properties of beef tallow as lubricating grease

2017 ◽  
Vol 69 (5) ◽  
pp. 645-654 ◽  
Author(s):  
Juozas Padgurskas ◽  
Raimundas Rukuiža ◽  
Ihor Mandziuk ◽  
Arturas Kupcinskas ◽  
Katerina Prisyazhna ◽  
...  
Keyword(s):  
Critical Load ◽  
Tribological Properties ◽  
Beef Tallow ◽  
Friction And Wear ◽  
Load Level ◽  
Synthesis Process ◽  
Polymer Additives ◽  
Lubricating Grease ◽  
Content Type ◽  
Thermally Processed

Purpose The purpose of this paper is to report on the tribological properties of beef tallow grease and improvements therein through modification with special processing, polymeric compounds and additives. Design/methodology/approach Pure original beef tallow grease was used as a biological lubricating grease reference material for the tribological research. Beef tallow was modified and synthesized by adding special biological anti-oxidant additives, LZ anti-wear additives, waste polyethylene terephthalate (PET) polymer compounds and thermally processed graphite. Findings Rheometric measurements indicate that the beef tallow grease modification technology used in this study enables control of the synthesis process to produce lubricants with the required microstructure. Investigation results of the tribological properties of differently modified greases show that beef tallow synthesized with polymer additives efficiently operates together with anti-wear additives to reduce friction and wear. The grease compound with thermally processed graphite has good tribological properties at 300 N load levels. The critical load level of lubricating greases could be significantly increased through the use of anti-wear additives and thermally processed graphite. Originality/value Investigation results of the tribological properties of differently modified beef tallow greases show that beef tallow synthesized with polymer additives efficiently operates together with anti-wear additives to reduce friction and wear. The critical load level of lubricating beef tallow greases could be significantly increased using anti-wear additives and thermally processed graphite.

Tribological properties of the epoxy resin-based solid lubricant coating modified by Kevlar fibers

2018 ◽  
Vol 70 (9) ◽  
pp. 1706-1713 ◽  
Author(s):  
Guotao Zhang ◽  
Yanguo Yin ◽  
Ting Xie ◽  
Dan Li ◽  
Ming Xu ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Epoxy Resin ◽  
Tribological Properties ◽  
Dry Friction ◽  
Friction And Wear ◽  
Solid Lubricant ◽  
Transfer Film ◽  
Wear Properties ◽  
Content Type ◽  
Friction And Wear Properties

Purpose This paper aims to obtain high mechanical and good tribological properties of epoxy resin-based coatings under dry friction conditions. Design/methodology/approach Bonded solid lubricant coatings containing Kevlar fibres were prepared by a spraying method. The friction and wear properties of the coatings were experimentally investigated with a face-to-face tribometre under dry friction conditions. Scanning electron microscopy, energy dispersive X-ray spectroscopy and 3D laser scanning technologies were used to characterise the tribological properties. The action mechanism of the Kevlar fibres on a solid lubricant transfer film was also analysed. Findings Adding Kevlar fibres can significantly improve the wear resistance of the coatings. When the Kevlar fibre content increases, the tribological properties of the coatings improve and then worsen. Superior properties are obtained with 0.03 g of Kevlar fibres. Appropriately increasing the load or speed is beneficial to the removal of the outer epoxy resin and the formation of a lubricant film. During friction, the solid lubricants wrapped in the epoxy resin accumulate on the surface to form a transfer film that shows a good self-lubricating performance. In the later friction stage, fatigue cracks occur on the solid lubricant film but cannot connect to one another because of the high wear resistance and the entanglement of the rod-like Kevlar fibres. Thus, no large-area film falls from the matrix, thereby ensuring the long-term functioning of solid lubricant coatings. Originality/value Epoxy resin-based solid lubricant coatings modified by Kevlar fibres were prepared, and their friction and wear properties were investigated. Their tribological mechanisms were also proposed. This work provided a basis for the analysis of the tribological properties and design of bonded solid lubricant coatings containing Kevlar fibres.

Improving wear resistance of aluminum by hydrophobic sol-gel-derived TiO2 film

2018 ◽  
Vol 70 (8) ◽  
pp. 1408-1413 ◽  
Author(s):  
Hongjin Zhao ◽  
Lei Cao ◽  
Yong Wan ◽  
Shuyan Yang ◽  
Jianguo Gao ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Stearic Acid ◽  
Design Methodology ◽  
Friction And Wear ◽  
Sol Gel ◽  
Industrial Applications ◽  
Content Type ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Increase Wear Resistance

Purpose The purpose of this paper is to increase wear resistance of aluminum. Design/methodology/approach The authors have studied the ways to improve the tribological performance of aluminum by assembling stearic acid on aluminum coated by sol-gel-derived TiO2 film. The samples were characterized by infrared spectroscopy, contact angle measurements and a macro friction and wear tester. Findings Enhanced wear resistance was clearly obtained after functionalization of TiO2 film on aluminum by stearic acid. Originality/value The relevant results might be helpful for guiding the surface modification of aluminum devices in industrial applications.

The effect of environmental humidity/water absorption on tribo-mechanical performance of polymers and polymer composites – a review

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kawaljit Singh Randhawa ◽  
Ashwin Patel
Keyword(s):  
Mechanical Properties ◽  
Polymer Composites ◽  
Tribological Properties ◽  
Fiber Reinforced Polymer ◽  
Content Type ◽  
Wear Rates ◽  
Mechanical And Tribological Properties ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Water Conditions

Purpose The mechanical and tribological properties of polymers and polymer composites vary with different environmental conditions. This paper aims to review the influence of humidity/water conditions on various polymers and polymer composites' mechanical properties and tribological behaviors. Design/methodology/approach The influence of humidity and water absorption on mechanical and tribological properties of various polymers, fillers and composites has been discussed in this paper. Tensile strength, modulus, yield strength, impact strength, COF and wear rates of polymer composites are compared for different environmental conditions. The interaction between the water molecules and hydrophobic polymers is also represented. Findings Pure polymer matrices show somewhat mixed behavior in humid environments. Absorbed moisture generally plasticizes the epoxies and polyamides and lowers the tensile strength, yield strength and modulus. Wear rates of PVC generally decrease in humid environments, while for polyamides, it increases. Fillers like graphite and boron-based compounds exhibit low COF, while MoS2 particulate fillers exhibit higher COF at high humidity and water conditions. The mechanical properties of fiber-reinforced polymer composites tend to decrease as the rate of humidity increases while the wear rates of fiber-reinforced polymer composites show somewhat mixed behavior. Particulate fillers like metals and advanced ceramics reinforced polymer composites exhibit low COF and wear rates as the rate of humidity increases. Originality/value The mechanical and tribological properties of polymers and polymer composites vary with the humidity value present in the environment. In dry conditions, wear loss is determined by the hardness of the contacting surfaces, which may not effectively work for high humid environments. The tribological performance of composite constituents, i.e. matrix and fillers in humid environments, defines the overall performance of polymer composite in said environments.

Tribology of Ge thin films on stainless steel

2017 ◽  
Vol 69 (2) ◽  
pp. 182-189
Author(s):  
Lubomir Krabac ◽  
Vladimir Pejaković ◽  
Vladislav Drinek ◽  
Nicole Dörr ◽  
Ewald Badisch
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Stainless Steel ◽  
Design Methodology ◽  
Friction And Wear ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Chemical Vapor Deposition Method ◽  
Content Type ◽  
Sliding Distance

Purpose The purpose of this paper is to study the friction and wear behavior of germanium (Ge) thin films deposited by low-pressure chemical vapor deposition method on a chromium (Cr)-nickel (Ni) stainless steel substrate after being exposed to relatively mild sliding conditions (low loads and sliding distances). Design/methodology/approach Wear and friction experiments were conducted with a 100Cr6 steel ball sliding against flat Ge thin-film-coated stainless steel sheets (ball-on-flat microtribometer, no lubricant, normal loads of 50-100 mN, initial Hertzian contact pressures of 385-485 MPa, total sliding distance up to 200 mm and room temperature). Findings Scanning electron microscopy results revealed that prepared Ge thin films consisted of two different morphologies: curved nanowires and cone-shaped nano-/microdroplets. Regarding friction and wear characteristics of the investigated samples, the substrates coated with Ge thin films did not affect the coefficient of friction significantly by load. The wear of the base material (Cr-Ni stainless steel) was not observed under the mentioned experimental conditions (see the “Design/methodology/approach” section); however, with increased sliding distance and/or applied load, a rupture of the Ge film and an exposure of the stainless steel substrate to the 100Cr6 ball can be expected. Furthermore, the observations suggest that the smearing of Ge nano- and microstructures, plastically deformed during tribotesting, over the surface exposed to the sliding contact is the dominant tribological process. Originality/value For the first time, the tribological interaction between Ge thin film and steel surface was investigated under dry sliding conditions using a ball-on-flat microtribometer, and the obtained results provide a useful base for the further research on tribology of Ge-based thin films.

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