Third Body Formation and the Wear of PTFE Fibre-Based Dry Bearings

1980 ◽  
Vol 102 (2) ◽  
pp. 236-245 ◽  
Author(s):  
J. K. Lancaster ◽  
D. Play ◽  
M. Godet ◽  
A. P. Verrall ◽  
R. Waghorne
Keyword(s):  
Photoelectron Spectroscopy ◽  
Friction And Wear ◽  
Resin Composite ◽  
X Rays ◽  
Third Body ◽  
Fibre Glass ◽  
Wear Rates ◽  
The Coefficient Of Friction ◽  
Considerable Degradation ◽  
Counterface Roughness

Dry bearing tests have been made with a PTFE fibre/glass fibre/phenolic resin composite against stainless steel to examine the influence of time of sliding, counterface roughness and load. The worn surfaces were examined by optical and scanning electron microscopy, energy dispersive analysis of X-rays (EDAX) and X-ray photoelectron spectroscopy (ESCA). It is shown that the coefficient of friction and the rate of wear are strongly influenced by the formation of third bodies on both sliding surfaces. The structure and composition of these third bodies depend on the time of sliding and the load, but are independent of counterface roughness. Wear of the PTFE composite appears to occur on several scales, and considerable degradation of PTFE is evident within the third body (transfer film) on the counterface. The significance of these observations to the measured friction and wear rates is discussed.

scholarly journals On the Microstructural, Mechanical and Tribological Properties of Mo-Se-C Coatings and Their Potential for Friction Reduction against Rubber

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1336
Author(s):  
Jorge Caessa ◽  
Todor Vuchkov ◽  
Talha Bin Yaqub ◽  
Albano Cavaleiro
Keyword(s):  
Carbon Content ◽  
Friction And Wear ◽  
Current Mode ◽  
Friction Reduction ◽  
Transition Metal Dichalcogenide ◽  
Butadiene Rubber ◽  
Wear Rates ◽  
Mechanical And Tribological Properties ◽  
The Coefficient Of Friction ◽  
Pin On Disk

Friction and wear contribute to high energetic losses that reduce the efficiency of mechanical systems. However, carbon alloyed transition metal dichalcogenide (TMD-C) coatings possess low friction coefficients in diverse environments and can self-adapt to various sliding conditions. Hence, in this investigation, a semi-industrial magnetron sputtering device, operated in direct current mode (DC), is utilized to deposit several molybdenum-selenium-carbon (Mo-Se-C) coatings with a carbon content up to 60 atomic % (at. %). Then, the carbon content influence on the final properties of the films is analysed using several structural, mechanical and tribological characterization techniques. With an increasing carbon content in the Mo-Se-C films, lower Se/Mo ratio, porosity and roughness appeared, while the hardness and compactness increased. Pin-on-disk (POD) experiments performed in humid air disclosed that the Mo-Se-C vs. nitrile butadiene rubber (NBR) friction is higher than Mo-Se-C vs. steel friction, and the coefficient of friction (CoF) is higher at 25 °C than at 200 °C, for both steel and NBR countersurfaces. In terms of wear, the Mo-Se-C coatings with 51 at. % C showed the lowest specific wear rates of all carbon content films when sliding against steel. The study shows the potential of TMD-based coatings for friction and wear reduction sliding against rubber.

Tribological performance of industrial polyamide-imide and its composite under different cooling conditions

2012 ◽  
Vol 32 (3) ◽  
Author(s):  
Huseyin Unal ◽  
Mehmet Kurt ◽  
Abdullah Mimaroglu
Keyword(s):  
Friction And Wear ◽  
Air Cooling ◽  
Atmospheric Conditions ◽  
Insulation Property ◽  
Wear Rates ◽  
Cooling Conditions ◽  
316 L Stainless Steel ◽  
The Coefficient Of Friction ◽  
Steel Disc ◽  
Aisi 316 L

Abstract Polyamide-imide (PAI) polymer is a high-temperature resistant polymer, which is used as contact breaker material because of its high electrical insulation property. The working conditions of contact breakers arise from the wear and friction problem conditions of these materials. Therefore, the tribological behavior of PAI polymer is important. In this study, the friction and wear performance of pure PAI polymer and PAI composite [PAI+12% graphite+3% polytetrafluoroethylene (PTFE)] were studied in two different cooling environmental conditions (with and without air cooling). Wear tests were carried out with the configuration of a polymer pin, on a rotating AISI 316 L stainless steel disc. Test conditions were atmospheric conditions, 50 N, 100 N, and 150 N loads and 0.5, 1.0, 2.0 and 3.0 m/s sliding speeds. For sliding without air cooling and sliding with air cooling, the results show that the coefficient of friction and wear rates for pure PAI and PAI+12% graphite+3% PTFE composite, slightly decrease and increase with the increase in applied load and sliding speed values, respectively. In addition, for the range of loads and sliding speeds of this study, low coefficients of friction and high specific wear rates are registered at sliding under air cooling conditions. Finally, the wear mechanism includes adhesive and abrasive processes.

scholarly journals Evaluation of Friction and Wear Behavior of Date Palm Fruit Syrup as an Environmentally Friendly Lubricant

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1589 ◽  
Author(s):  
Mazin Tahir ◽  
Abdul Samad Mohammed ◽  
Umar Azam Muhammad
Keyword(s):  
Tribological Properties ◽  
Friction And Wear ◽  
Date Palm ◽  
Wear Behavior ◽  
Normal Load ◽  
Environmentally Friendly ◽  
Potential Candidate ◽  
Palm Fruit ◽  
Wear Rates ◽  
The Coefficient Of Friction

The effect of various operational factors, such as sliding speed, normal load and temperature on the tribological properties of Date palm fruit syrup (DPFS) as an environmentally friendly lubricant, is investigated. Ball-on-disc wear tests are conducted on mild steel samples in the presence of DPFS as a lubricant under different conditions and the coefficient of friction and wear rate are measured. Scanning electron microscopy, stylus profilometry, and Fourier transform infrared spectroscopy are used to evaluate the wear tracks to determine the underlying wear mechanisms. Results showed that DPFS has excellent tribological properties in terms of low friction and low wear rates making it a potential candidate to be used as a lubricant in tribological applications.

Wear Mechanism of Ceramics and Surface Topography

1986 ◽  
Vol 108 (1) ◽  
pp. 9-15 ◽  
Author(s):  
T. Hisakado
Keyword(s):  
Cross Sections ◽  
Friction And Wear ◽  
Cross Sectional ◽  
Wear Rates ◽  
Contact Points ◽  
The Coefficient Of Friction ◽  
The Mean ◽  
New Criterion ◽  
Theoretical Results ◽  
Wear Tests

Assuming that harder asperities sliding on a flat surface were semicylindrical with the hemispherical ends, whose surface consisted of a series of spherical micro-asperities, effects of the number of contact points n, total area Sp of the cross-sections of grooves ploughed by harder asperities and depth of plastic zone on the coefficient of friction and wear for ceramics were theoretically analyzed. To verify theory, wear tests with various ceramic pins and a Si3N4 disk were carried out at a sliding speed of 1.63 m/s and under load of 0.98 N with no lubrication. The sizes of wear scratches on the worn surfaces were measured by means of a Talysurf and SEM photographs. The wear rates of the pins and Si3N4 disks increased with an increase in the mean cross-sectional area Sp/n of the scratches. This trend agreed with the theoretical results, which also showed that the Sp values were proportional to the wear rates. Theory also indicated the existence of a new criterion applicable to estimation of the wear rate.

Effect of Phosphorus on the Friction and Wear Characteristics of Cu-Sn-P Alloys

1979 ◽  
Vol 101 (2) ◽  
pp. 201-206 ◽  
Author(s):  
Y. Taga ◽  
K. Nakajima
Keyword(s):  
Photoelectron Spectroscopy ◽  
Friction And Wear ◽  
Structural Changes ◽  
Surface Concentration ◽  
Wear Characteristics ◽  
X Ray ◽  
The Matrix ◽  
Pin On Disc ◽  
The Coefficient Of Friction ◽  
Friction And Wear Characteristics

The effects of phosphorus on the friction and wear characteristics of Cu-5 at. percent Sn-P alloys containing 1–5 at. percent P were studied using a pin on disc apparatus. The results showed that the decrease in both the coefficient of friction and the rate of wear became conspicuous with the increase in quantity of Cu3P coexisting in the matrix; its amount increases with the content of phosphorus. The structural changes in the surface of the specimen due to heating in a vacuum were observed by using Auger electron spectroscopy and X-ray photoelectron spectroscopy. It was seen that the surface concentration of phosphorus strongly increased after heating at 573K, whereas the diffusion of tin atoms was markedly retarded. It was concluded from these results that the behavior of phosphorus atoms in the surface during sliding played an important role in the friction and wear characteristics of Cu-Sn-P alloys.

scholarly journals A Factorial Design to Numerically Study the Effects of Brake Pad Properties on Friction and Wear Emissions

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Jens Wahlström
Keyword(s):  
Factorial Design ◽  
Coefficient Of Friction ◽  
Friction And Wear ◽  
Friction Material ◽  
Particulate Emissions ◽  
Third Body ◽  
Wear Process ◽  
Disc Brakes ◽  
The Coefficient Of Friction ◽  
Contact Situation

Airborne particulate emissions originating from the wear of pads and rotors of disc brakes contribute up to 50% of the total road emissions in Europe. The wear process that takes place on a mesoscopic length scale in the contact interfaces between the pads and rotors can be explained by the creation and destruction of contact plateaus. Due to this complex contact situation, it is hard to predict how changes in the wear and material parameters of the pad friction material will affect the friction and wear emissions. This paper reports on an investigation of the effect of different parameters of the pad friction material on the coefficient of friction and wear emissions. A full factorial design is developed using a simplified version of a previously developed cellular automaton approach to investigate the effect of four factors on the coefficient of friction and wear emission. The simulated result indicates that a stable third body, a high specific wear, and a relatively high amount of metal fibres yield a high and stable mean coefficient of friction, while a stable third body, a low specific wear, a stable resin, and a relatively high amount of metal fibres give low wear emissions.

Friction and Wear Studies on Polyphenylene Sulfide Filled with a Complex Mixture

2012 ◽  
Vol 184-185 ◽  
pp. 1400-1403
Author(s):  
Li Guo ◽  
Huan Qin Zhu ◽  
Yuan Bao Sun
Keyword(s):  
Wear Rate ◽  
Friction And Wear ◽  
Narrow Range ◽  
Tribological Behavior ◽  
Complex Mixture ◽  
Polyphenylene Sulfide ◽  
Particulate Form ◽  
The Coefficient Of Friction ◽  
Molybdenum Concentrate ◽  
Counterface Roughness

The tribological behavior of PPS filled with molybdenum-concentrate (MC) deposit from Armenia was studied. The deposit MC was a complex mixture of compounds such as MoS2, SO2, CuS, Al2O3, and others. Whereas MC as the filler in particulate form reduced the steady state wear rate of PPS, the optimum reduction in wear was found to occur with the addition of PTFE along with PPS. The behavior of PPS composites made with MC and PTFE sliding against a steel counterface was investigated as a function of the MC and PTFE proportions, sliding speed, and counterface roughness. Of all the above factors, the change in MC proportion, while PTFE was also present, had the greatest effect on the reduction in wear rate. The variation of the coefficient of friction was found to be in the narrow range of 0.27-0.33. The lowest wear rate was found in the case of PPS+ 17vol.%MC+10vol.%PTFE composite sliding at 1.5 m/s against a counterface roughness of 0.1 μm Ra.

Counterface Roughness Effect on the Dry Steady State Wear of Self-Lubricating Polyimide Composites

1984 ◽  
Vol 106 (2) ◽  
pp. 177-184 ◽  
Author(s):  
D. F. Play
Keyword(s):  
Fourier Transform ◽  
Steady State ◽  
Friction And Wear ◽  
Unit Length ◽  
Wave Length ◽  
Statistical Data Analysis ◽  
Wear Rates ◽  
Polyimide Composites ◽  
The Fourier Transform ◽  
Counterface Roughness

Initial counterface topography influences both running-in and steady state wear rates of polymers. But governing roughness parameters are difficult to isolate because of their strong dependences and their statistical natures. Distributions of RT, RA, R.M.S., Skewness, Kurtosis, profile slopes, number of peaks per unit length, radii of curvature of peak asperity and Fourier transform were considered to characterize the isotropic roughness of the abraded steel disks. Two polyimide composites with PTFE and CF x powders were chosen for the pins. Correlations between parameters, friction and linear steady state wear were obtained through statistical data analysis. Radii of curvature, profile slopes or RA, and number of peaks govern friction and wear in different ways depending on fillers. However, for both materials, wear increases with average slopes or RA and decreases with an increase of number of peaks and radii of curvature. Skewness governs also the results but Kurtosis and wave length of the maximum of the Fourier transform are useless to explain the results.

Sliding wear and friction of Si3N4-SiC-based ceramic composites containing hexagonal boron nitride

1998 ◽  
Vol 212 (5) ◽  
pp. 381-387 ◽  
Author(s):  
R Westergård ◽  
A Åhlin ◽  
N Axén ◽  
S Hogmark
Keyword(s):  
Boron Nitride ◽  
Photoelectron Spectroscopy ◽  
Friction And Wear ◽  
Hexagonal Boron Nitride ◽  
Ceramic Composites ◽  
Wear Behaviour ◽  
Friction Coefficients ◽  
X Ray ◽  
Wear Rates ◽  
Low Level

The friction and wear behaviour of a series of new Si3N4-SiC-based ceramic composites, intended for face seal applications, has been investigated with cylinder-on-disc equipment. In particular, the influence of water and vapour on the friction, wear and tribo-film formation has been studied. The ceramics consisted of Sis3N4 and SiC in the proportions 7:3, to which 0, 4 or 8 wt% of hexagonal boron nitride was added as a solid lubricant. All specimens were produced by hot isostatic pressing. X-ray diffraction and scanning electron microscopy were used to reveal the phase composition and microstructure respectively. The hardness was assessed using Vickers indentation. The chemical composition of the tribo-films was studied with X-ray photoelectron spectroscopy. The major results are that both friction and wear showed distinct low and high levels. The high friction level corresponded to friction coefficients between 0.4 and 0.9 and wear rates between 104 and 105 μm3/Nm. The low level corresponded to friction coefficients between 0.02 and 0.1, and wear rates between 10 and 103 μm3/Nm. When water or saturated vapour was present in the tribo-system, both friction and wear were low. All surfaces produced in the low level were smooth, covered by a thin well-adhering tribo-film while the high level resulted in strongly oxidized and patchy tribo-film covered by wear particles.

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