scholarly journals Effect of normal load and roughness on the nanoscale friction coefficient in the elastic and plastic contact regime

2013 ◽  
Vol 4 ◽  
pp. 66-71 ◽  
Author(s):  
Aditya Kumar ◽  
Thorsten Staedler ◽  
Xin Jiang
Keyword(s):  
Plastic Deformation ◽  
Friction Coefficient ◽  
Tribological Behavior ◽  
Normal Load ◽  
Theoretical Models ◽  
Sample Surface ◽  
Fused Silica ◽  
Diamond Like Carbon ◽  
Load Range ◽  
Applied Normal Load

The influence of applied normal load and roughness on the tribological behavior between the indenter and sample surface during nanoindentation-based scratching has been experimentally investigated by using different surfaces (fused silica and diamond-like carbon) featuring various degrees of roughness. At a sufficiently low applied normal load, wherein the contact is elastic, the friction coefficient is constant. However, at increased normal loads the contact involves plastic deformation and the friction coefficient increases with increasing normal load. The critical load range for a transition from predominantly elastic to plastic contact, between the indenter and sample surface, increases with increasing size of indenter and decreases with roughness. Distinct differences between the present experimental results and the existing theoretical models/predictions are discussed.

Characterisation of Plasticity Response for Reciprocating Sliding Wear Test of Ti-6Al-4V under Variables Normal Load

2015 ◽  
Vol 1087 ◽  
pp. 350-354 ◽  
Author(s):  
D. Harun ◽  
Abdul Latif Mohd Tobi ◽  
A. Singh Chaal ◽  
Ramdziah Md. Nasir
Keyword(s):  
Plastic Deformation ◽  
Sliding Wear ◽  
Wear Track ◽  
Normal Load ◽  
Surface Profile ◽  
Wear Test ◽  
Wear Scar ◽  
Reciprocating Sliding ◽  
Applied Normal Load ◽  
Reciprocating Sliding Wear

Reciprocating sliding wear test of uncoated titanium alloy, Ti-6Al-4V is investigated using pin-on-flat arrangement under variable applied normal load. The wear scar produced by the reciprocating sliding wear test is analysed by surface profile examination using 2D and 3D optical microscope (OM) and Scanning Electron Microscope (SEM). Through SEM, the energy-dispersive X-ray spectroscopy (EDX) is used to characterise the composition of the substance on the worn surface. The hardness value of the wear scar is investigated at three regions which are; worn, unworn and the end of the wear track using Micro Vickers Hardness Test. The presence of moderate oxygen composition and the increasing in hardness value at the end of wear track suggesting evidence of plastic deformation. The increase in hardness value at the end of wear track indicates increase in plastic deformation with increasing applied normal load.

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.

Micro-Tribological Behavior of Boron Carbide Self-Mated Pairs

2007 ◽  
Vol 336-338 ◽  
pp. 1740-1742
Author(s):  
Fang Wu ◽  
Sheng Ming Xu ◽  
Song Zhe Chen ◽  
Lin Yan Li ◽  
Gang Xu ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Boron Carbide ◽  
Tribological Properties ◽  
Tribological Behavior ◽  
Normal Load ◽  
The Self ◽  
Sliding Velocity ◽  
Oxidation Treatment ◽  
Sliding Distance

Tribological behavior of B4C-SiC self-mated pairs was studied, and pre-oxidation treatment was adopted to improve the tribological properties of B4C-SiC. At the same SiC content, self-friction coefficient of B4C-SiC decreases with the increase of sliding distance, normal load, and sliding velocity; while the increasing of SiC content leads to increase of both self-friction coefficient and ware rate, which was determined to be within the range of 0.8×10-6~5.8×10-6 mm3·N-1·m-1. Pre-oxidation treatment of the B4C-SiC resulted in the formation of B2O3/H3BO3 lubricant layers, which effectively reduced the self-friction coefficient.

Dry sliding of composites with PBT matrix and micro glass beads on steel

2014 ◽  
Vol 66 (3) ◽  
pp. 424-433 ◽  
Author(s):  
Constantin Georgescu ◽  
Lorena Deleanu ◽  
Mihail Botan
Keyword(s):  
Friction Coefficient ◽  
Tribological Behavior ◽  
Early Stage ◽  
Normal Load ◽  
Glass Beads ◽  
Polybutylene Terephthalate ◽  
Sem Images ◽  
Neat Polymer ◽  
Content Type ◽  
Sliding Distance

Purpose – This research aims to characterize the tribological behavior of polybutylene terephthalate (PBT) and PBT composites with micro glass beads (MGB) on steel, in dry conditions and on a block-on-ring tester, pointing out the influence of sliding distance and speed. The tribology of PBT and its composites is still in an early stage because this thermoplastic polyester requires accurate technological and thermal treatment. Design/methodology/approach – The composites were produced by ICEFS Savinesti Romania and contain PBT grade Crastin6130NC010 (as supplied by Du Pont), 0.5 […] 1.0 per cent (weight) Relamyd B-2Nf (polyamide grade produced by ICEFS, for a better dispersion of MGB), 1 per cent (weight) black carbon for technological and tribological reasons and different micro glass beads (MGB) concentrations (10.0 and 20.0 per cent weight). Tests were done for different sliding distances (2,500, 5,000 and 7,500 m) and speeds (0.5, 1.0 and 1.5 m/s) and a normal load of 5 N. Findings – The friction coefficient and the wear parameter (as mass loss of polymeric blocks) pointed out a good tribological behavior for these composites. Scanning electron microscope (SEM) images revealed particular aspects of PBT local transfer on steel. Also, 10 per cent MGB in PBT reduces wear, especially for longer distances (75,000 m) and higher speeds (0.5 and 0.75 m/s); the friction coefficient is only slightly increased up to 0.23, being less influenced by the speed and the sliding distance as compared to neat polymer. Originality/value – PBT and PBT composites could become challengers for replacing materials in applications similar to tested ones. Even the neat polymer exhibits a good tribological behavior. The composites have a lower sensibility to higher speeds and sliding distances for the applied load.

Tribological Behavior of Cubic Boron Nitride Film Sliding Against Diamond

1995 ◽  
Vol 117 (4) ◽  
pp. 629-633 ◽  
Author(s):  
Shuichi Watanabe ◽  
Shojiro Miyake ◽  
Masao Murakawa
Keyword(s):  
Friction Coefficient ◽  
Boron Nitride ◽  
Normal Load ◽  
Cubic Boron Nitride ◽  
Maximum Load ◽  
Nitride Film ◽  
Cathode Plasma ◽  
Load Range ◽  
Diamond Indenter ◽  
Plating Method

Cubic boron nitride (c-BN) film was deposited onto a silicon substrate by means of a magnetically enhanced plasma ion plating method utilizing a hot cathode plasma discharge in parallel magnetic field. In this study, the friction and wear behaviors of the c-BN film, particularly when it came into sliding contact with diamond, were investigated using a reciprocating tribometer in an applied normal load range of 0.1 ~ 4.9 N. The results showed that the friction coefficient of the c-BN film sliding against the diamond indenter tended to decrease as the load increased, and was very low, exhibiting values of 0.03 ~ 0.065 at the maximum load of 4.9 N. Furthermore, the study confirmed that the friction coefficient of annealed c-BN film was lower than that of as-deposited c-BN film throughout the whole load range. Judging from the results of comparable investigations in which c-BN film came into contact with other materials such as c-BN compact, SiC and stainless steel, the wear performance and peeling resistance of the c-BN film proved to be significantly better in the case of contact with diamond.

Contact mechanics of elastic-plastic fractal surfaces and static friction analysis of asperity scale

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wujiu Pan ◽  
Xiaopeng Li ◽  
Xue Wang
Keyword(s):  
Plastic Deformation ◽  
Fractal Dimension ◽  
Friction Coefficient ◽  
Contact Mechanics ◽  
Normal Load ◽  
Boundary Value ◽  
Static Friction ◽  
Content Type ◽  
Elastic Plastic ◽  
Static Friction Coefficient

Purpose The purpose of this paper is to provide a static friction coefficient prediction model of rough contact surfaces based on the contact mechanics analysis of elastic-plastic fractal surfaces. Design/methodology/approach In this paper, the continuous deformation stage of the multi-scale asperity is considered, i.e. asperities on joint surfaces go through three deformation stages in succession, the elastic deformation, the elastic-plastic deformation (the first elastic-plastic region and the second elastic-plastic region) and the plastic deformation, rather than the direct transition from the elastic deformation to the plastic deformation. In addition, the contact between rough metal surfaces should be the contact of three-dimensional topography, which corresponds to the fractal dimension D (2 < D < 3), not two-dimensional curves. So, in consideration of the elastic-plastic deformation mechanism of asperities and the three-dimensional topography, the contact mechanics of the elastic-plastic fractal surface is analyzed, and the static friction coefficient nonlinear prediction model of the surface is further established. Findings There is a boundary value between the normal load and the fractal dimension. In the range smaller than the boundary value, the normal load decreases with fractal dimension; in the range larger than the boundary value, the normal load increases with fractal dimension. Considering the elastic-plastic deformation of the asperity on the contact surface, the total normal contact load is larger than that of ignoring the elastic-plastic deformation of the asperity. There is a proper fractal dimension, which can make the static friction of the contact surface maximum; there is a negative correlation between the static friction coefficient and the fractal scale coefficient. Originality/value In the mechanical structure, the research and prediction of the static friction coefficient characteristics of the interface will lay a foundation for the understanding of the mechanism of friction and wear and the interaction relationship between contact surfaces from the micro asperity-scale level, which has an important engineering application value.

scholarly journals Impact of Perfluoro and Alkylphosphonic Self-Assembled Monolayers on Tribological and Antimicrobial Properties of Ti-DLC Coatings

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2365 ◽  
Author(s):  
Michal Cichomski ◽  
Milena Prowizor ◽  
Ewelina Borkowska ◽  
Ireneusz Piwoński ◽  
Anna Jędrzejczak ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Control Sample ◽  
Antimicrobial Properties ◽  
Self Assembled Monolayers ◽  
Diamond Like Carbon ◽  
Dispersive Component ◽  
Load Range ◽  
Dlc Coatings ◽  
Assembled Monolayers ◽  
Self Assembled

The diamond-like carbon (DLC) coatings containing 1.6%, 5.3% and 9.4 at.% of Ti deposited by the radio frequency plasma enhanced chemical vapor deposition (RF PECVD) method on the silicon substrate were modified by n-decylphosphonic acid (DP) and 1H, 1H, 2H and 2H-perfluorodecylphosphonic acid (PFDP). The presence of perfluoro and alkylphosphonic self-assembled monolayers prepared by the liquid phase deposition (LPD) technique was confirmed by Fourier transform infrared spectroscopy (FTIR). It was shown that DP and PFDP monolayers on the surface of titanium incorporated diamond-like carbon (Ti-DLC) coatings had a huge influence on their wettability, friction properties, stability under phosphate- and tris-buffered saline solutions and on antimicrobial activity. It was also found that the dispersive component of surface free energy (SFE) had a significant influence on the value of the friction coefficient and the percentage value of the growth inhibition of bacteria. The dispersive component of SFE caused a reduction in the growth of bacteria and the friction coefficient in mili- and nano-newton load range. Additionally, both self-assembled monolayers prepared on Ti-DLC coatings strongly reduced bacterial activity by up to 95% compared to the control sample.

Development of a New Tip Assembly for Lateral Force Microscopy and Its Application to Thin Film Magnetic Media

1995 ◽  
Vol 117 (2) ◽  
pp. 244-249 ◽  
Author(s):  
C.-J. Lu ◽  
Zhaoguo Jiang ◽  
D. B. Bogy ◽  
T. Miyamoto
Keyword(s):  
Thin Film ◽  
Friction Coefficient ◽  
Normal Load ◽  
Lateral Force ◽  
Magnetic Media ◽  
Load Range ◽  
Force Microscopy ◽  
Normal Forces ◽  
Carbon Coated ◽  
Scratch Tests

In a Lateral Force Microscope (LFM), appropriate spring constants of the tip assembly are essential for obtaining proper normal loads for wear or scratch tests and good lateral force signals. We developed a new tip assembly design for which the lateral and normal springs can be changed independently. It was installed on a LFM where two optical heads are used to detect the lateral and normal deflections of the tip assembly for simultaneous measurements of the surface topography and friction force. Reliable calibration procedures for the LFM are presented. The LFM was used to measure the lateral forces in wear tests under various normal forces for thin film magnetic disks with and without a carbon overcoat. The friction coefficient is constant in the load range where there is no wear and increases with normal load after the tip starts to damage the surface. The carbon-coated disk has a lower friction coefficient and can support larger normal loads without wear.

Dry Sliding Tribological Behavior of Columnar-Grained Fe2B Intermetallic Compound Under Different Loads

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Kemin Li ◽  
Zhifu Huang ◽  
Ting Min ◽  
Jiamei Liu ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Intermetallic Compound ◽  
Wear Rate ◽  
Abrasive Wear ◽  
Laser Scanning ◽  
Tribological Behavior ◽  
Normal Load ◽  
Dry Sliding ◽  
Dynamic Friction Coefficient ◽  
Worn Surface

The dry sliding tribological behavior of a columnar-grained Fe2B intermetallic compound under different normal loads was evaluated by scanning electron microscopy (SEM), XPS, and 3D laser scanning microscope. The results indicated that under a load of 12 N, after a 35 min break-in period, the dynamic friction coefficient decreased from 0.78 to about 0.6 and this low value was maintained until the end of test. When the normal load increased from 4 N to 20 N, both the average friction coefficient and wear rate values initially decreased and then increased. The lowest values of the average friction coefficient and wear rate were obtained under a load of 12 N. As the load increased from 4 N to 12 N, a complete film formed on worn surface. Nevertheless, when the load increased to 16 N, severe self-induced vibration occurred and a corrugated ribbon appeared on the surface. Furthermore, severe damage on the worn surface was caused by cycling vibration under the 20 N load. Under 4 N and 12 N, the main wear mechanism was abrasive wear, while under a load of 20 N, fracture wear and abrasive wear were the mian wear mechanisms. The friction products were composed of B2O3, H3BO3, SiO2, and FexOy. More specifically, Fe2O3 was generated under 4 N load, Fe2O3 and Fe3O4 were produced under 12 N load, and the mixture of FeO, Fe2O3, and Fe3O4 appeared under 20 N load.

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.

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