scholarly journals A Novel Inward Gradient Self-Lubrication Layer with Soft Alloys and Its Lubricating Mechanism

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Songshan Yan ◽  
Ling Qin ◽  
Rui Hu ◽  
Zuomin Liu
Keyword(s):  
Gradient Distribution ◽  
Lubricating Film ◽  
Lubricating Layer ◽  
Lubrication Layer ◽  
The Matrix ◽  
Lubricating Property ◽  
Soft Metal ◽  
Worn Surface ◽  
High Frequency Induction ◽  
Lubricating Mechanism

A novel ceramic composite inward gradient distribution layer has been developed. The layer is a lubricating layer in which soft-metal lubricants are compounded into the ceramic matrix by high frequency induction infiltrating method. The design of the layer and its lubricating mechanism are investigated in the paper. The results show that the property of the layer greatly depends on the wetting angle of the soft-metal lubricants on the matrix and the proportion of Ag, Cu, Sn, and Pb as well as the infiltrating parameters. Based on a lot of experiments, a novel inward gradient layer with Pb28Sn19Ag6Cu has been developed. The layer has an excellent lubricating property (friction coefficient about 0.2~0.3 at 600°C). The research reveals the lubricating mechanism, observing the phenomenon that the soft-metal in the matrix diffuses out of the frictional surface, and measures the lubricating film thickness as about 20 μm on the worn surface.

scholarly journals Friction and Wear Characteristics of Microporous Interface Filled with Mixed Lubricants of M50 Steel at Different Loads

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2934
Author(s):  
Xiyao Liu ◽  
Zhiwei Lu ◽  
Hao Dong ◽  
Yan Cao ◽  
Xueming Qian
Keyword(s):  
Flow Behavior ◽  
Interfacial Structure ◽  
Laser Additive Manufacturing ◽  
Load Range ◽  
Lubricating Film ◽  
Lubricating Layer ◽  
Lubrication Characteristics ◽  
Worn Surface ◽  
M50 Steel

Improving the tribological performance of M50 steel under the conditions of wide load range is of great significance. In this study, the interfacial structure of surface micropores filled with Sn–Ag–Cu or Sn–Ag–Cu/whisker carbon nanotubes (whiskerCNT) of M50 material was prepared by laser additive manufacturing and high-temperature infiltration. From 2 to 22 N, the lubrication characteristics of Sn–Ag–Cu and whiskerCNT in surface micropores of M50 was investigated. Results indicate that Sn–Ag–Cu can precipitate to the worn surface and form a lubricating layer, which has a good lubricating effect. Moreover, the flow behavior of Sn–Ag–Cu on a worn surface can play the role of crack healing. At higher load, the strength of the lubricating film is enhanced by whiskerCNT, which renders the lubricating film not vulnerable to premature rupture.

scholarly journals Dynamics of non-wetting drops confined in a Hele-Shaw cell

2018 ◽  
Vol 845 ◽  
pp. 245-262 ◽  
Author(s):  
Ludovic Keiser ◽  
Khalil Jaafar ◽  
José Bico ◽  
Étienne Reyssat
Keyword(s):  
Viscous Dissipation ◽  
Settling Velocity ◽  
Wetting Transition ◽  
Lubricating Film ◽  
Low Viscosity ◽  
Asymptotic Models ◽  
Lubricating Layer ◽  
Lubrication Layer ◽  
Viscous Droplets ◽  
Surrounding Liquid

We experimentally investigate the sedimentation of a non-wetting drop confined between two parallel walls. The whole system is immersed in a bath of liquid of low viscosity and a lubricating film may be dynamically formed between the drop and the walls of the cell. Depending on the thickness of the film and on the viscosity ratio between the droplet and the surrounding liquid, viscous dissipation localizes either in the lubrication layer or in the bulk of the drop. The velocity of the droplet is non-trivial as the thickness of the lubricating layer may depend on the interplay between interfacial tension and viscous dissipation. Interestingly, thin films whose nanometric thickness is set by long range intermolecular interactions may lubricate efficiently the motion of highly viscous droplets. We derive asymptotic models that successfully capture the settling velocity of the drop in the different regimes observed experimentally. The effect of partial wetting is finally illustrated by a sharp increase of the velocity of the drops that we attribute to a wetting transition.

Properties of Jute Fibers Reinforced Friction Materials

2011 ◽  
Vol 399-401 ◽  
pp. 474-477
Author(s):  
Yun Hai Ma ◽  
Su Qiu Jia ◽  
Bao Gang Wang ◽  
Wei Ye ◽  
Jin Tong ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Friction Coefficient ◽  
Wear Debris ◽  
Temperature Decrease ◽  
Heating Condition ◽  
Friction Materials ◽  
Abrasive Particles ◽  
Jute Fibers ◽  
The Matrix ◽  
Worn Surface

Jute fibers reinforced friction materials were prepared by mold and heat treatment. The friction coefficients of 3wt.%,9wt.% and 12wt.% jute fibers reinforced friction materials were bigger than that of the materials without jute fibers in the heating condition. The friction coefficient of 6 wt.% jute fibers reinforced friction materials was bigger than that of the materials without jute fibers below 250°C. The friction coefficient of jute fibers reinforced friction materials deceased with the temperature decrease in the cooling condition. The friction coefficient of the materials with free-jute fibers raised from 350-250°C and reduced at the temperature lower than 250°C.Wear rates of the friction materials raised with temperature rise for jute fibers carbonization led to the matrix became loose. With jute fibers content rise worn surface of the reinforced materials became from smooth to rough. There were pits, grooves, abrasive particles, pulled out fibers and wear debris on the worn surfaces. Abrasive wear was the main wear mechanism.

Study of Wear Properties of In Situ TiB/TiC Reinforced Ti1100 Composites

2013 ◽  
Vol 550 ◽  
pp. 107-113
Author(s):  
Xiao Lu Gong ◽  
Fei Zhao ◽  
Di Zhang
Keyword(s):  
Shear Stress ◽  
Wear Debris ◽  
Matrix Alloy ◽  
Stress Distributions ◽  
Wear Properties ◽  
Wear Process ◽  
The Matrix ◽  
Pin On Disc ◽  
Worn Surface

The tribological performances of in-situ (TiB + TiC) / Ti1100 composites prepared by casting and the matrix alloy were tested by pin-on disc mode. The worn surface and wear debris were investigated by SEM. The models of the composites during the wear process were simulated by ABAQUS FEA software. The analysis shows the stress distributions inside the composites under the different shear stress. The wear mechanism of the composites is probed.

Al2O3-TiC/Fe Functionally Gradient Material Prepared by SHS Casting

2011 ◽  
Vol 704-705 ◽  
pp. 6-10
Author(s):  
Wan Hong Zang ◽  
Chang Lun Yuan ◽  
Yan Li
Keyword(s):  
Gradient Material ◽  
Matrix Metal ◽  
Exterior Surface ◽  
Gradient Distribution ◽  
Functionally Gradient Material ◽  
Surface Composite ◽  
Functionally Gradient ◽  
High Temperature Synthesis ◽  
The Matrix ◽  
Shs Casting

Al2O3-TiC particles reinforced iron matrix functionally gradient material is successfully fabricated by combining the methods of self-propagating high-temperature synthesis (SHS) with casting. The SHS products are analyzed by SEM and XRD and EDS. The results show that the grain size of the particle is round 1μm~3μm, the composition of the Al2O3-TiC/ Fe surface composite takes on a gradient distribution from outside to inside, and transforms gradually to the matrix metal. The hardness below 0.5mm from exterior surface of the functionally gradient materials increases dramatically and gradually changes to the hardness of the matrix. Key words: In situ generation; SHS; Casting; Surface composite material; FGM

scholarly journals Al/Graphene/CNT hybrid composites: Hardness and sliding wear studies

2021 ◽  
Vol 49 (2) ◽  
pp. 414-421
Author(s):  
Manjunath Naik ◽  
L.H. Manjunath ◽  
Vishwanath Koti ◽  
Avinash Lakshmikanthan ◽  
Praveennath Koppad ◽  
...  
Keyword(s):  
Wear Rate ◽  
Sliding Wear ◽  
Hybrid Composites ◽  
Wear Behavior ◽  
Lubricating Layer ◽  
Wear And Friction ◽  
Bulk Hardness ◽  
Graphene Content ◽  
Worn Surface ◽  
Sliding Distance

Graphene and carbon nanotubes are two carbon based materials known for their unique wear and friction properties. It would be quite interesting to understand the wear behavior of aluminium hybrid composites when these two nanosize reinforcements are incorporated into it. The hybrid composites with varying weight fractions of graphene (1, 2, 3 and 5 wt.%) and fixed CNT content of 2 wt.% were produced using powder metallurgy technique. The effect of varying graphene content on hardness and sliding wear of hybrid composites was studied. The wear tests were done as per ASTM G-99 standard with fixed sliding velocity (2 m/s) and sliding distance (1200 m) but varying applied load (10 - 30 N). Worn surface analysis was conducted using scanning electron microscope to arrive at wear mechanisms responsible for wear of aluminium and its hybrid composites. Increase in graphene content led to increase in bulk hardness with highest value of 61 RHN for hybrid composite with 3 wt.% graphene content. The wear rate of hybrid composites was found to be decreasing with enhancement in graphene content. Lower wear rate in hybrid composites was due to the formation of lubricating layer on the worn surface.

Tribological behavior of WS2/oil-impregnated porous polyimide solid/liquid composite system

2019 ◽  
Vol 71 (3) ◽  
pp. 459-466 ◽  
Author(s):  
Zhen Yan ◽  
Dong Jiang ◽  
Xiaoming Gao ◽  
Can Zhang ◽  
Ming Hu ◽  
...  
Keyword(s):  
Composite System ◽  
Tribological Behavior ◽  
Content Type ◽  
Lubricating Film ◽  
Lubricant Oil ◽  
Hydrocarbon Chains ◽  
Before And After ◽  
Lubricating Property ◽  
Abnormal Phenomenon ◽  
Solid Liquid

Purpose This paper aims to study the tribological behavior of the WS2/oil-impregnated porous polyimide (PPI) solid/liquid composite system, in which both PFPE (perfluoropolyether) and SiCH (silahydrocarbons) oils with different hydrocarbon chains were used, respectively. Lubricating mechanism of the composite system was also explored. Design/methodology/approach The tribological behaviors of the WS2 films against the PPI cylindrical pins before and after immersing oil were evaluated under different loads by a reciprocating-type ball-on-disc tribometer. Findings The composite system exhibited the low and stable friction coefficient after the running-in stage, and the lubricant oil played a positive effect. It was found that the WS2/PFPE composite system exhibited more excellent lubricating property, although sole SiCH far exceeds PFPE in lubrication. The abnormal phenomenon mainly resulted from the influence of the oil amount. XRD results on the wear track surfaces indicated that PFPE and SiCH oils with different hydrocarbon chains were likely to preferentially adsorb to the edge plane and basal plane of the WS2 crystals, respectively. Originality/value In previous studies, liquid lubricants were directly dripped or spin-coated on the solid lubricant surface. Based on its potential advantage in application, the tribological behavior and mechanism of the solid lubricating film/oil-impregnated PPI composite system were investigated in this study.

The synergistic lubricating mechanism of Sn-Ag-Cu and C60 on the worn surface of M50 self-lubricating material at elevated loads

2019 ◽  
Vol 777 ◽  
pp. 271-284 ◽  
Author(s):  
Xiyao Liu ◽  
Xiaoliang Shi ◽  
Guanchen Lu ◽  
Xiaobin Deng ◽  
Hongyan Zhou ◽  
...  
Keyword(s):  
Lubricating Material ◽  
Worn Surface ◽  
Lubricating Mechanism

Gas Plasma Treatment of Sputtered Carbon Thin Film and Enhancement of its Properties

1988 ◽  
Vol 140 ◽  
Author(s):  
J.P. Sharma ◽  
P.B. Narayan ◽  
A.S. Brar
Keyword(s):  
Plasma Treatment ◽  
Plasma Etching ◽  
Carbon Layer ◽  
Magnetic Media ◽  
Ion Diffusion ◽  
Lubricating Film ◽  
Gas Plasma ◽  
Lubricating Layer ◽  
The Media ◽  
Frictional Instability

AbstractIn magnetic recording, the metallic magnetic media are protected from corrosion and wear by a thin sputtered carbon layer. The latter also acts as a self-lubricating film during the interaction of the media with the ceramic read \write head pad material. Since the surface energy of carbon is high, it tends to absorb and chemisorb environmental constituents such as oxygen, nitrogen, water vapor and hydrocarbons. These could then react with the head\media interface and form heterogeneous layers of “frictional polymers”. These changes in carbon lead to frictional instability and friction build-up. Low temperature gas plasma treatment of sputtered carbon layer was found to improve the surface properties and the frictional instability problems. Use of a mixture of argon and carbon tetrafluoride gases led to the formation of a very thin self-lubricating layer, probably a fluorocarbon. The surface also becomes smooth. This is because of thecombined reaction of chemical reaction, ion-diffusion, ion-penetration and plasma etching. This reaction product was found to be prominently present at the grain boundaries and other morphological inhomogeneities, thereby strengthening the weak areas and improving the tribo-performance of the media.

Sliding Tribological Behavior of Al–Fe–V–Si–Graphite Solid-Lubricating Composites at Elevated Temperatures

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Hui Tan ◽  
Shuai Wang ◽  
Jun Cheng ◽  
Shengyu Zhu ◽  
Jun Yang
Keyword(s):  
Elevated Temperatures ◽  
Matrix Composites ◽  
Wear Properties ◽  
Alloy Matrix ◽  
Graphite Composite ◽  
Mechanical And Tribological Properties ◽  
Lubricating Film ◽  
Effect Of Copper ◽  
Graphite Composites ◽  
Worn Surface

Aluminum alloy metal matrix composites (Al-MMCs) have been considered as promising materials for aerospace and automotive industries due to their excellent balance of physical, mechanical, and tribological properties. In the present work, the Al–Fe–V–Si alloy matrix composites with 0–20 wt. % copper-coated graphite were fabricated by hot-pressed sintering. The dry sliding tests were carried out at various temperatures ranging from room temperature (RT) to 350 °C. The microstructure, phase, hardness, and worn surface of the sintered composites were examined in detail. The effect of copper-coated graphite amount on the properties of the composite was also investigated. The results show that the Al–Fe–V–Si–graphite composites mainly consist of α-Al, Al8Fe2Si intermetallic, and graphite phases. The addition of Cu-coated graphite can decrease the friction coefficient and wear rate from RT to 350 °C. The Al–Fe–V–Si–graphite composite containing 10 wt. % copper-coated graphite exhibits better wear properties than other composites. The favorable lubricating properties were attributed to the tribolayer with graphite lubricating film formed on the worn surface.

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