The tribological performance of W-DLC in solid–liquid lubrication system addivated with Cu nanoparticles

2021 ◽  
Author(s):  
Dong shan Li ◽  
Ning Kong ◽  
Ruishan Li ◽  
Boyang Zhang ◽  
Yongshun Zhang ◽  
...  
Keyword(s):  
Test Temperature ◽  
Applied Load ◽  
Tribological Performance ◽  
Dominant Factor ◽  
Lubrication System ◽  
Cu Nanoparticles ◽  
Friction Test ◽  
Dlc Film ◽  
Test Conditions ◽  
Solid Liquid

Abstract Judicious selection of additives having chemical and physical compatibility with the DLC films may help improving the triboligical properties and durability life of DLC-oil composite lubrication systems. In this study, Cu nanoparticles were added to PAO6 base oil to compose a solid-liquid composite lubrication system with W-DLC film. The effects of nanoparticle concentration, test temperature and applied load on tribological performance were systematically studied by a ball-on-disk friction test system. The tribological results illustrated that Cu nanoparticles could lower the coefficient of friction (COF) and dramatically reduce the wear rates of W-DLC films. The optimal tribological behavior was achieved for the 0.1 wt.% concentration under 30 ℃ and the applied load of 100 N. The test temperature and applied load were vital influencing factors of the solid–liquid lubrication system. The bearing effect and soft colloidal abrasive film of spherical Cu nanoparticle contributed to the excellent tribological performance of the composite lubrication system under mild test conditions, meanwhile, the local delamination of W-DLC film and oxidation were the main causes of the friction failure under harsh test conditions. With test temperature and applied loads increase the degree of graphitization of the W-DLC film increased. In conclusion, there are several pivotal factors affecting the tribological performance of solid–liquid lubrication systems, including the number of nanoparticles between rubbing contact area, graphitization of the worn W-DLC films, tribofilms on the worn ball specimens and oxidation formed in friction test, and the dominant factor is determined by the testing condition.

The tribological performance of DLC-based coating under the solid–liquid lubrication system with sand-dust particles

Wear ◽  
2013 ◽  
Vol 297 (1-2) ◽  
pp. 972-985 ◽  
Author(s):  
Jianwei Qi ◽  
Liping Wang ◽  
Fengyuan Yan ◽  
Qunji Xue
Keyword(s):  
Tribological Performance ◽  
Dust Particles ◽  
Lubrication System ◽  
Solid Liquid ◽  
Sand Dust

Regulation on tribological performance of tungsten-doped DLC coatings by Choline Chloride-Urea and -Thiourea Deep Eutectic Solvents

2022 ◽  
Author(s):  
Fan Yang ◽  
Yuting Li ◽  
Zhaofan Yue ◽  
Qingbo Fan ◽  
Hao Li ◽  
...  
Keyword(s):  
Surface Properties ◽  
Friction And Wear ◽  
Choline Chloride ◽  
Deep Eutectic Solvents ◽  
Tribological Performance ◽  
Lubrication System ◽  
Low Friction ◽  
Dlc Coatings ◽  
Solid Liquid ◽  
Tribochemical Interaction

Abstract Solid-liquid composite lubrication system has attracted an increased interest for low friction and wear. Nevertheless, the effect of mechanical and surface properties of the solid materials, especially the mechanical and surface properties governed by doping elements, on the tribological performance solid-liquid composite lubrication system is still not well comprehended. Here, we reported the effect of W content on the mechanical and surface properties of W-DLC coatings as well as the tribological properties of W-DLC coatings under (choline chloride-urea and choline chloride-thiourea) deep eutectic solvents lubrication. Although the wear of W-DLC coatings under dry friction increases with W content, the wear under DESs is slight when coatings show excellent wettability to DESs or a DES-derived tribochemical film is formed. We demonstrate that the tribological behavior of W-DLC and DESs composite lubrication system is related to the mechanical properties of W-DLC coatings together with the contact angle and tribochemical interaction between DESs and W-DLC coatings.

Simple Correlations and Analysis of Cuttings Transport With Newtonian and Non-Newtonian Fluids in Horizontal and Deviated Wells

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Mehmet Sorgun
Keyword(s):  
Pure Water ◽  
Newtonian Fluids ◽  
The Other ◽  
Cuttings Transport ◽  
Pressure Losses ◽  
Test Conditions ◽  
Bed Thickness ◽  
Solid Liquid ◽  
Cuttings Bed ◽  
Pipe Rotation

In this study, simple empirical frictional pressure losses and cuttings bed thickness correlations including pipe rotation are developed for solid-liquid flow in horizontal and deviated wellbores. Pipe rotation effects on cuttings transport in horizontal and highly inclined wells are investigated experimentally. Correlations are validated experimental data with pure water as well as four different non-Newtonian fluids for hole inclinations from horizontal to 60 degrees, flow velocities from 0.64 m/s to 3.56 m/s, rate of penetrations from 0.00127 to 0.0038 m/s, and pipe rotations from 0 to 250 rpm. Pressure drop within the test section, and stationary and/or moving bed thickness are recorded besides the other test conditions. The new correlations generated in this study are believed to be very practical and handy when they are used in the field.

Sliding Induced Nanocrystals on Si

2005 ◽  
Author(s):  
Srinivas Guruzu ◽  
Hong Liang
Keyword(s):  
Atomic Force Microscope ◽  
Surface Characterization ◽  
Applied Load ◽  
Length Scale ◽  
Sliding Surface ◽  
Si Substrate ◽  
Atomic Force ◽  
Test Conditions ◽  
Boundary Properties ◽  
Nanometer Length Scale

Our previous research has shown that Ga pin sliding again Si induces nanometer length scale crystals. In this research, we continued on with an In pin with one stroke slides on Si substrate. Applied load was varied for sliding Surface characterization was conducted using an atomic force microscope. Results showed that triangular-shaped nanocrystals were formed on Si surfaces. The height and side length of these nanocrystals depend on test conditions. In this paper, we report our findings in crystal structures and boundary properties.

Strength of Sulfur-Linked Elastomers

1996 ◽  
Vol 69 (4) ◽  
pp. 577-590 ◽  
Author(s):  
H. Chun ◽  
A. N. Gent
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Crack Propagation ◽  
Test Temperature ◽  
Effective Rate ◽  
Master Curves ◽  
Universal Form ◽  
Wlf Equation ◽  
Test Conditions

Abstract Fracture energies have been determined for tearing through a sheet of a polysulfide elastomer, and for peeling apart two sheets bonded together with sulfur interlinks. Measurements were made over wide ranges of rate of crack propagation and test temperature. By shifting curves at various temperatures along the rate axis, using shift factors aT calculated from the “universal” form of the WLF equation, master curves were obtained for tear and peel energy vs. rate of tear or peel at the glass transition temperature Tg about −55°C. These master curves of strength vs. effective rate of crack propagation at Tg were closely similar to those obtained previously for several hydrocarbon elastomers: BR, SBR and EPR; interlinked with C-C bonds. Thus, under comparable test conditions the strength of the present polysulfide elastomer with sulfur crosslinks is similar to that for hydrocarbon elastomers with C-C crosslinks. The question then arises: Why are sulfur-vulcanized elastomers stronger in common experience than peroxide-cured ones? Possible reasons are discussed.

Stress-Induced Change of the Microstructure and Strength of Modified 9Cr-1Mo Steel Under Fatigue and Creep Loadings at Elevated Temperatures

2017 ◽  
Author(s):  
Taichi Shinozaki ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Activation Energy ◽  
Applied Stress ◽  
Test Temperature ◽  
Elevated Temperatures ◽  
Critical Value ◽  
Atomic Diffusion ◽  
Dominant Factor ◽  
Martensitic Structure ◽  
Creep Tests ◽  
Microstructure Change

The change of the lath martensitic structure in modified 9Cr-1Mo steel was observed in the specimens after the fatigue and creep tests using EBSD (Electron Back-Scatter Diffraction). The Kernel Average Misorientation (KAM) value obtained from the EBSD analysis were used for the quantitative evaluation of the change in the lath martensitic texture. It was found that the average KAM values of the fractured specimens decreased clearly after 107−108 cycles of the fatigue loading at temperatures higher than 500°C when the amplitude of the applied stress exceeded a critical value. This change corresponded to the disappearance of the lath martensitic structure. The critical value decreased monotonically with the increase of the test temperature. This microstructure change decreased the strength of the alloy drastically. It was found that the change of the microstructure started at a certain time at each test temperature as a function of the amplitude of the applied stress. There was the critical stress at which the microstructure change started at each test temperature higher than 500°C, and the activation energy of the change was determined as a function of temperature and the amplitude of the applied stress. The dominant factor of the microstructure change was the stress-induced acceleration of the atomic diffusion of the component elements in the alloy. In order to improve the long-term reliability of the alloy, it is very important to increase the activation energy by modifying the microstructure of this alloy.

Taguchi optimization of various parameters for tribological performance of polyalphaolefins based nanolubricants

2020 ◽  
pp. 135065012097229
Author(s):  
Homender Kumar ◽  
AP Harsha
Keyword(s):  
Kinematic Viscosity ◽  
Applied Load ◽  
Tribological Performance ◽  
Control Factor ◽  
Wear Properties ◽  
Multiwalled Carbon ◽  
Taguchi Optimization ◽  
Frictional Characteristic ◽  
Antiwear Properties ◽  
Analytical Tools

This research paper addresses the optimization of various control parameters by using the Taguchi method to assess the tribological properties of PAOs based nanolubricants. The concentration of COOH-functionalized multiwalled carbon nanotubes (MWCNTs), applied load, sliding velocity and kinematic viscosity of polyalphaolefins (PAOs) were selected as process parameters or control factor. The MWCNTs at a varying concentration (0.025-0.15 wt.%) were blended separately in PAOs to formulate the nanolubricants. The tribological experimentations were performed by Taguchi’ L18 mixed orthogonal array using “ball on disc” type tribometer. The analysis of variance (ANOVA) was adopted to estimate the most prominent factors influencing the tribological performance of nanolubricants. The statistical results showed that the applied load, followed by a concentration of MWCNTs conferred the most significant impact on the frictional characteristic. In contrast, the kinematic viscosity of PAOs, followed by concentration of MWCNTs has been observed the most significant influencing factors on the antiwear properties of nanolubricants. The probabilistic rationale for the advancement in friction and wear properties were assessed through various analytical tools.

The Effect of Temperature and Strain Rate on Selected Lead-Free Solder Alloys

2004 ◽  
Author(s):  
Jayamalar Vijayen ◽  
James G. Maveety ◽  
Emily L. Allen
Keyword(s):  
Strain Rate ◽  
Test Temperature ◽  
Bulk Solder ◽  
Effect Of Temperature ◽  
Strain Rate Effects ◽  
Lap Shear ◽  
Test Conditions ◽  
Rate Effects ◽  
Free Solder ◽  
Strength And Ductility

Abstract The temperature and strain rate effects on the shear properties of selected Pb-free solders were investigated. The experiments were performed using single lap shear specimens. All testing was performed using a standard tensile test metrology. The following results were found: 1) Sn-3.5 wt.% Ag outperformed all the other solders in terms of its mechanical strength at all test conditions due to the formation of Ag3Sn precipitates in the bulk solder and Cu6Sn5 intermetallic formation along the interface. However, ductility was sacrificed as this solder strain hardens. 2) The strength and ductility of the solder joint is strongly dependent on the test temperature and strain rate. Data in this work reflects a decrease in strength and ductility when the test temperature is increased. This phenomenon can be attributed to the increase in energy as temperature is increased to overcome dislocation barriers such as impurities and grain boundaries that impede the motion of dislocation. When strain rate is increased, the amount of plastic deformation experienced by the solder increases and more dislocations are formed. Due to the increase in proximity and number of the dislocations, the net result is that motion of the dislocations are hindered thus requiring more stress to deform the material.

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