What Causes Low Friction? — What Causes High Friction?

2005 ◽  
Author(s):  
Y. Elaine Zhu ◽  
Steve Granick
Keyword(s):  
Friction Coefficient ◽  
Recent Work ◽  
Frictional Force ◽  
Friction And Wear ◽  
Normal Load ◽  
Low Friction ◽  
Strategic Design ◽  
Modern Methods ◽  
Design Requirements ◽  
The Many

The design of tribological interfaces is often motivated by a quest to minimize friction and wear. Among the many strategic design principles that have been developed to this end, the simple idea of decoupling frictional force from normal load is especially attractive. Recent work from this laboratory demonstrates that under certain conditions, it is possible to reduce this coupling significantly with the result that the friction coefficient appears to be very low. However, the materials design requirements to achieve this end are rather stringent. Furthermore, modern methods enable one under some conditions to measure directly the structure and motions of lubricants during tribological sliding.

The Effect of Sliding Speed on Friction and Wear of RBD Palm Olein

2013 ◽  
Vol 315 ◽  
pp. 951-955 ◽  
Author(s):  
Samion Syahrullail ◽  
Jazair Yahya Wira ◽  
W.B. Wan Nik ◽  
Chiong Ing Tiong
Keyword(s):  
Friction Coefficient ◽  
Friction And Wear ◽  
Palm Olein ◽  
Normal Load ◽  
Mineral Oil ◽  
Low Friction ◽  
Sliding Speed ◽  
Rbd Palm Olein

In this paper, the effect of sliding speed on the anti-friction of RBD palm olein was investigated using four-ball tribotester. The speeds were varied from 800 to 1400 rpm. The normal load was set to 40 kg and the test oil was heated up to 75 °C before the experiments. The result showed that palm olein has low friction coefficient compared to additive-free paraffinic mineral oil.

Surface Topography and Friction Dynamics in Brake Systems Described by a Cellular Automaton

2005 ◽  
Author(s):  
M. Mueller ◽  
G. P. Ostermeyer
Keyword(s):  
Friction Coefficient ◽  
Kinetic Energy ◽  
Cellular Automata ◽  
Relative Velocity ◽  
Friction And Wear ◽  
Normal Load ◽  
Friction Behavior ◽  
Plastic Deformations ◽  
Parameter Dependent ◽  
Friction Dynamics

For the description of a friction event it is necessary to understand the friction coefficient μ as a process-parameter dependent not only on the surface-structure but also for instance on the relative velocity, normal load, temperature and the event itself. In brake systems, for example, growing and destroying processes of hard thin patches determine the friction power and the transfer of kinetic energy into heat and plastic deformations, such as wear. So the interaction of friction and wear is given by an equilibrium of flow of different processes resulting in growing effects or lowering effects on the friction coefficient itself [2]–[4]. The aim of this paper is to show the detailed interaction of this topographical dynamics and the friction behavior with the Method of Cellular Automata.

Friction and wear behavior of hydrogenated diamond-like carbon coating against titanium alloys under large normal load and variable velocity

2017 ◽  
Vol 69 (2) ◽  
pp. 199-207 ◽  
Author(s):  
Jun Liu ◽  
Zhinan Zhang ◽  
Zhe Ji ◽  
Youbai Xie
Keyword(s):  
Friction Coefficient ◽  
Service Life ◽  
Carbon Coating ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Normal Load ◽  
Diamond Like Carbon ◽  
Content Type ◽  
Friction And Wear Behavior ◽  
Dlc Coating

Purpose This paper aims to investigate the effects of reciprocating frequency, large normal load on friction and wear behavior of hydrogenated diamond-like carbon (H-DLC) coating against Ti-6Al-4V ball under dry and lubricated conditions. Design/methodology/approach The friction and wear mechanisms are analyzed by scanning electron microscope, energy dispersive spectroscopy and Raman spectroscopy. Findings The results show that as reciprocating frequency increases under lubricated conditions, the friction coefficient decreases first and then increases. When the reciprocating frequency is 2.54 Hz, the value of friction coefficient reaches the minimum. The friction reduction is because of the transformation from sp3 to sp2, the formation of transfer layer on Ti-6Al-4V ball and the reduction in viscous friction, whereas the increase of friction coefficient is related to wear. In dry conditions, the friction coefficient is between 0.06 and 0.1. And, the service life of H-DLC coating decreases with the increase in reciprocating frequency and normal load. Research limitations/implications It is confirmed that adding the lubricant could prolong the service life of H-DLC coating and reduce friction and wear efficiently. And, the wear mechanisms under dry and lubricated conditions encompass abrasive wear and adhesive wear. Originality/value The results are helpful for application of diamond-like carbon coating.

The Mechanical Properties and Friction and Wear Behavior of C/C-SIC

2010 ◽  
Author(s):  
Gao Wen ◽  
Chongsheng Long ◽  
Tang Rui ◽  
Jiping Wang
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Normal Load ◽  
Carbon Matrix ◽  
Specific Wear Rate ◽  
Sliding Speed ◽  
Wear Rates ◽  
Sic Composites

Carbon fiber reinforced carbon-silicon carbide composites (C/C-SiC) were prepared by chemical volume infiltration (CVI) method and reaction melt infiltration (RMI) technique of silicon liquid to carbon reinforce carbon matrix composites. The friction and wear behaviors of C/C-SiC composites at various loads and sliding speeds were investigated by MRH-3 block-on-ring tribometer at room temperature under water lubricating conditions. Furthermore, the morphologies, phase of the worn surface and the debris were observed, examined and analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDAX) respectively. Experimental results showed that the C/C-SiC composites had a better wear resistence, and the friction coefficient under water lubricated conditions is about 0.02–0.06. The influence of sliding speed on the friction coefficients and the specific wear rate of C/C-SiC is more obvious than that of normal load when the load is less than 200N (inclueded200N). The friction coefficient and the specific wear rate of C/C-SiC decreased as the sliding velocity increased. At the sliding speed higher than 2m/s, the friction coefficient is less than 0.02. The specific wear rates is at a low level about (2×10−7mm3/Nm–5×10−8mm3/Nm).

The Effects of PTFE Content on Microstructures and Properties of Composite Brushing Plating Coating

2014 ◽  
Vol 936 ◽  
pp. 1025-1030 ◽  
Author(s):  
Yang Wang ◽  
Xiu Fang Cui ◽  
Guo Jin ◽  
Hai Peng Li ◽  
Wei Zheng ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Friction And Wear ◽  
Energy Dispersive Spectrometer ◽  
Solid Material ◽  
Low Friction ◽  
X Ray ◽  
Binding Characteristics ◽  
Structure Morphology ◽  
Lubricating Property ◽  
Coefficient Stability

Polytetrafluoroethylene (PTFE) is known as a solid material with high lubricating property and low friction coefficient. The application of PTFE is significant to improve the tribological properties of coating. In this paper, Scanning electron microscopy (SEM), Energy Dispersive Spectrometer (EDS), X-ray diffractometry (XRD), Microhardness test and friction and wear experiment are adopted to study the effects of PTFE content on the structure, morphology and properties of coating. The results show that the addition of PTFE particles can reduce spherical particle size and increase the hardness and friction properties of coating when typical cauliflower shaped druse and excellent interface binding characteristics are maintained. If the content of PTFE is too much, some area of coating is prone to powder hoarding which may lead to the decrease of coating density, hardness, and friction coefficient stability.

Tribological Properties Between a-C:H Coatings and SiO2 at High Temperature

2020 ◽  
Author(s):  
Noritsugu Umehara ◽  
Kota Konishi ◽  
Motoyuki Murashima ◽  
Takayuki Tokoroyama
Keyword(s):  
High Temperature ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Friction And Wear ◽  
Wear Track ◽  
Severe Damage ◽  
Friction Test ◽  
Low Friction ◽  
Disk Friction

Abstract Tribological properties of a-C:H coatings has been investigated in various friction conditions. It is clear that temperature and mating materials give effects on tribological properties. In this study, we especially focus on the effect of mating material on its tribological properties of a-C:H coatings. Ball-on-disk friction test is conducted between a-C:H coating and 5 kinds of mating material, which is SiC, SiC(O)_800 (SiC oxidized at 800°C), SiC(O)_1050°C, SiC(O)_1300°C, and Quartz glass. It is found that a-C:H coatings shows low friction coefficient and low specific wear rate when O/Si ratio of the element content of mating material is 2, in other words, mating material is SiO2. In the wear scar of a-C:H coating after friction test with SiC, severe damage was confirmed. It is considered that a-C:H coating and SiO2 show low adhesion even at high temperature, which leads low friction and wear. Compared SiC(O) with Quartz, the friction coefficients with a-C:H coatings are respectively 0.013 and 0.038. Even though SiC(O) and Quartz are both SiO2, the tribological properties are different. On the wear track of SiC(O), transferred things from a-C:H coating are confirmed.

Friction and wear tester

2020 ◽  
Vol 86 (8) ◽  
pp. 66-71
Author(s):  
V. E. Red’kin ◽  
Yu. S. Tkachenko ◽  
P. O. Sukhodaev ◽  
A. I. Lyamkin
Keyword(s):  
Friction Coefficient ◽  
Friction And Wear ◽  
Metal Cutting ◽  
Normal Load ◽  
Graphite Powder ◽  
Friction Torque ◽  
Tribological Characteristics ◽  
Friction Machine ◽  
Industrial Oil ◽  
Flat Spiral

A compact and simple in design device (friction machine) for testing materials for friction and wear is developed. The device is intended for determination of the wear resistance and friction coefficient of structural, frictional and antifriction materials, as well as the tribological characteristics of lubricants. The measurement system of the device includes spring helical and flat spiral elastic elements, combined in one node and designed to measure the normal force and friction torque, respectively. Metal-cutting machines can be used as an external drive of the device. The friction machine was tested when measuring the wear rate and the value of the friction coefficient of the samples of cast iron SCh20, brass L63, technical aluminum A7, as well as modified aluminum A7 with improved mechanical characteristics. The materials were tested in tandem with a counter-sample made of hardened steel 95Kh18 according to the ball-ring scheme in dry friction mode and in boundary lubrication mode using I-20A industrial oil at a normal load of 50 N and a linear velocity in the contact zone of 0.5 m/sec. The wear degree was estimated by the weight loss. The obtained results are characterized by the sufficient accuracy and reproducibility. A severe wear of brass is observed at a given testing load. Tests of the aluminum samples modified with ultrafine diamond-graphite powder UDP-AG obtained from explosives showed an increase in the tribological characteristics by 10 – 18%.

Friction and wear of argon-implanted silicon crystals

1994 ◽  
Vol 9 (1) ◽  
pp. 91-95 ◽  
Author(s):  
J. Lekki ◽  
Z. Stachura ◽  
N. Preikschas ◽  
B. Cleff ◽  
M. Cholewa ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Single Crystals ◽  
Friction And Wear ◽  
Strong Influence ◽  
X Ray Diffraction ◽  
Low Friction ◽  
X Ray ◽  
Silicon Crystals ◽  
Xrd Techniques ◽  
Pin On Disk

Silicon 〈111〉 single crystals were implanted with 70 keV Ar ions to the dose of 1017 ions/cm2. Next, the friction coefficient between a Si crystal and a hard steel ball was measured using a pin-on-disk setup in air and in vacuum. The wear tracks were measured using a surface profilometer. For measurements performed in vacuum, a strong influence of implantation on friction force and wear tracks was found. The microstructure of the samples was subsequently investigated using RBS, ERD, and x-ray diffraction (XRD) techniques. Micro-RBS measurements showed that Ar had been removed from the wear tracks, despite their continued exhibition of low friction.

A Comparative Study on the Tribological Behavior of SAE-AISI 1055 Steel and Brass (CuZn39Pb2) a Pin on Disc Type of Contact

2019 ◽  
Vol 397 ◽  
pp. 147-160
Author(s):  
Bougoffa Mohammed Seyf Eddine ◽  
Mebrouki Noura
Keyword(s):  
Friction Coefficient ◽  
Friction And Wear ◽  
Test Bench ◽  
Tribological Behavior ◽  
Wear Behavior ◽  
Normal Load ◽  
Wear Loss ◽  
Initial Surface ◽  
Sliding Speed ◽  
Friction And Wear Behavior

The paper assesses and compares the friction and wear behavior of SAE-AISI 1055 steel and brass (CuZn39Pb2) under dry sliding condition. The tribological behavior was investigated and compared by conducting two different experiments, the first experiment conducted on a CSM tribometer, and the second experiment was carried out on a test bench in horizontal lathe machine where device holder pin is fabricated and mounted on a test bench and a rotating disc, varying the normal load exert on the disc by the pin and the rotation speed of the disc. These tests consisted of measuring friction coefficient and wear loss of samples. Experiments are carried out in normal load 5-10 N, sliding speed 0.24-0.35 and 0.48 m/s. Variations of coefficient of friction during sliding at different initial surface roughness, normal load and sliding speed are investigated. Results show that the two alloys had different friction and wear behavior, for steel friction coefficient increase slowly with the increase of normal load and sliding speed. For brass friction coefficient decreases with the increase of normal load and sliding speed. On the other hand, it is also found that wear loss increase with sliding distance. Microscopic of worn surfaces for each alloy were carried out and compared.

Friction and Wear Behavior Evaluation of DLC Films Grown in Multilayer of Carbon and Silicon

2014 ◽  
Vol 802 ◽  
pp. 392-397
Author(s):  
Patrícia Cristiane Santana da Silva ◽  
Gislene Valdete Martins ◽  
Evaldo José Corat ◽  
Vladimir Jesus Trava-Airoldi
Keyword(s):  
Friction Coefficient ◽  
Friction And Wear ◽  
Wear Behavior ◽  
High Hardness ◽  
Low Friction ◽  
Dlc Coatings ◽  
Hard Materials ◽  
Dc Discharge ◽  
Pulsed Dc ◽  
Pulsed Dc Discharge

Excellent tribological properties of hard materials surface are desirable in several sectors of industry. Diamond-like carbon (DLC) coatings are well known for their low friction, excellent wear resistance, and high hardness. In this work, DLC films were deposited on AISI M2 steel using a modified PECVD pulsed-DC discharge. Multilayer of carbon and silicon were grown, alternately. Samples were produced with different layer thickness for carbon and silicon, and the same parameters for each material layer, in order to investigate friction coefficient in each layer, evaluate rate deposition variation and the gradient behavior of different layers. Raman spectroscopy was used to verify the structural arrangement of carbon atoms. The films were also characterized by scanning electron microscopy and EDX. Tribological tests were performed to observe adhesion between layers and substrate, friction, and wear. The results showed the variation of friction coefficient and that deposition rate declines when increasing number of layers.

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