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.

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.

Vibration of a Rotating Asymmetric Shaft Supported in Asymmetric Bearings

1968 ◽  
Vol 10 (3) ◽  
pp. 252-261 ◽  
Author(s):  
H. F. Black ◽  
A. J. McTernan
Keyword(s):  
Natural Frequencies ◽  
Equations Of Motion ◽  
Forced Vibrations ◽  
Variation Method ◽  
Approximate Theory ◽  
Cross Sectional ◽  
Mass Unbalance ◽  
The Mean ◽  
Theoretical Results ◽  
Good Agreement

The parametrically excited vibrations of this system with assumed small asymmetry of the shaft cross-section are discussed in terms of the motion of a symmetric shaft having the mean cross-sectional flexibility, and the equations of motion are solved by the approximate perturbation-variation method of Hsu. Both features yield a more lucid appreciation of the motions expected than previous treatments: in particular, simpler explicit expressions for unstable bounds are given and forced vibrations due to mass unbalance are discussed with greater facility. The practically important case of nearly coincident natural frequencies is examined. The theoretical results are compared with analogue computation: good agreement with the approximate theory is found even for quite large shaft asymmetry.

scholarly journals The Dynamics of the S(1D)+H2/D2 Reactions at Low Temperature via Statistical Simulations

2020 ◽  
Vol 3 (1) ◽  
pp. 9-16
Author(s):  
Tomas Gonzalez-Lezana ◽  
Pascal Larrégaray ◽  
Laurent Bonnet
Keyword(s):  
Cross Sections ◽  
Quantum Model ◽  
Space Theory ◽  
Collisional Energy ◽  
Energy Regime ◽  
Phase Space Theory ◽  
The Mean ◽  
Statistical Approaches ◽  
Theoretical Results ◽  
Good Agreement

Two different statistical approaches, the statistical quantum model (SQM) and the mean potential phase space theory (MPPST), have been employed to calculate the integral cross sections for the reactive collisions between S(1D) and H2/ D2  in the low energy regime (below 0.3 eV collisional energy). The rate constant for the S(1D) + H2 → SH + H reaction has been also obtained and compared with previously reported experimental and theoretical results. The good agreement shows the capability of these two methods to study the dynamics of these complex-forming atom-diatom processes in the present energy regime.

scholarly journals Biomechanical Evaluation on the Bilateral Asymmetry of Complete Humeral Diaphysis in Chinese Archaeological Populations

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1843
Author(s):  
Yuhao Zhao ◽  
Mi Zhou ◽  
Haijun Li ◽  
Jianing He ◽  
Pianpian Wei ◽  
...  
Keyword(s):  
Cross Sections ◽  
Torsional Rigidity ◽  
Distribution Patterns ◽  
Group Differences ◽  
Micro Ct ◽  
Cross Sectional ◽  
Bilateral Asymmetry ◽  
Biomechanical Evaluation ◽  
The Mean ◽  
Humeral Diaphysis

Diaphyseal cross-sectional geometry (CSG) is an effective indicator of humeral bilateral asymmetry. However, previous studies primarily focused on CSG properties from limited locations to represent the overall bilateral biomechanical performance of humeral diaphysis. In this study, the complete humeral diaphyses of 40 pairs of humeri from three Chinese archaeological populations were scanned using high-resolution micro-CT, and their biomechanical asymmetries were quantified by morphometric mapping. Patterns of humeral asymmetry were compared between sub-groups defined by sex and population, and the representativeness of torsional rigidity asymmetry at the 35% and 50% cross-sections (J35 and J50 asymmetry) was testified. Inter-group differences were observed on the mean morphometric maps, but were not statistically significant. Analogous distribution patterns of highly asymmetrical regions, which correspond to major muscle attachments, were observed across nearly all the sexes and populations. The diaphyseal regions with high variability of bilateral asymmetry tended to present a low asymmetrical level. The J35 and J50 asymmetry were related to the overall humeral asymmetry, but the correlation was moderate and they could not reflect localized asymmetrical features across the diaphysis. This study suggests that the overall asymmetry pattern of humeral diaphysis is more complicated than previously revealed by individual sections.

Orthogonal tests of the lubricating performance of SnO2 nanoparticles in poly-alfa-olefine oil

2021 ◽  
pp. 135065012110377
Author(s):  
Bing-Xu Wang ◽  
Fan Wu ◽  
Xiuming Zhang ◽  
Yongfeng Yuan ◽  
Shaoyi Guo ◽  
...  
Keyword(s):  
Friction And Wear ◽  
Normal Load ◽  
Sno2 Nanoparticles ◽  
Protective Layer ◽  
Wear Loss ◽  
Wear Depth ◽  
Shearing Resistance ◽  
The Coefficient Of Friction ◽  
Orthogonal Tests ◽  
Wear Tests

The tribological properties of SnO2 nanofluids were investigated using ball-on-plate reciprocating sliding wear tests. It was found that the coefficient of friction was reduced by 34.9% using 3 wt% SnO2 nanoparticles. The wear width and wear depth were reduced by 42% and 50.1%, respectively, using 2 wt% SnO2 nanoparticles. In the orthogonal tests, the frequency had the greatest influence on the friction and wear loss. Additionally, the optimal working conditions were a normal load of 50 N, a motion frequency of 1 Hz, and a surface roughness of 500–600 nm. Additionally, the excellent tribological performance of SnO2 nanofluids could be attributed to the formation of a tribo-film with a low shearing resistance due to the oleic acid and a protective layer due to the embedment of SnO2 nanoparticles.

A Theoretical Derivation of the Similarity of Dynamic Compaction Processes of Powder Media in Dies

1986 ◽  
Vol 108 (2) ◽  
pp. 147-152
Author(s):  
Yukio Sano
Keyword(s):  
Cross Sections ◽  
Dynamic Compaction ◽  
Simple Type ◽  
Theoretical Derivation ◽  
Cross Sectional ◽  
Density Distributions ◽  
Powder Medium ◽  
Compaction Energy ◽  
The Mean ◽  
Compaction Processes

Multiple shock compactions of powder media within a die with a rigid punch are theoretically investigated. First, similarity of dynamic compaction processes for a powder medium of a simple type is exhibited through nondimensionalized one-dimensional equations. The similarity is established after determination of three parameters, i.e., the ratio S* of the lateral surface to the cross-sectional area of the medium, the ratio M* of the mass of the punch to that of the powder medium filled in the die, and the compaction energy per unit powder volume e. The similarity indicates that the particle velocity, specific volume and pressure have the same variation with respect to nondimensional time at all points in the medium with various cross-sections and initial lengths so long as S* is kept fixed at a certain value, i.e., at the same proportional nondimensional point in the medium. The density distributions of the green compacts are necessarily identical, and so is the mean density in all compactions. Second, it is shown in one of the nondimensionalized equations that wall frictional influence in a compaction where S* → 0 is not present, while the wall frictional influence is extremely large when S* is very large, which implies that the mean densities of the compacts are larger in compactions with smaller S*. Two types of compactions can be obtained for any powder medium because the equation used is applicable to any medium.

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.

Dry sliding friction and wear behavior of self-lubricating wollastonite filled polycarbonate composites

2015 ◽  
Vol 67 (1) ◽  
pp. 22-29 ◽  
Author(s):  
Akin Akinci
Keyword(s):  
Wear Rate ◽  
Friction And Wear ◽  
Sliding Friction ◽  
Wear Behavior ◽  
Xrd Analysis ◽  
Dry Sliding ◽  
Wear Performance ◽  
Content Type ◽  
Wear Rates ◽  
Wear Tests

Purpose – The purpose of this paper is to investigate the friction and wear performance of pure polycarbonate (PC) and 5-30 per cent wollastonite-filled (by weight) PC were comparatively evaluated under dry sliding conditions. Wear tests were carried out at room temperature under the loads of 5-20 N and at the sliding speeds of 0.5-1.5 m/s. Design/methodology/approach – The microstructures of the wollastonite, pure PC and composites were examined by optical microscopy, scanning electron microscopy, energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis. The friction and wear tests were realized using a pin-on-disk arrangement against the hardened AISI 4140 steel. Findings – The result of this study indicated that the coefficients of friction wear rate of the materials were significantly influenced by an increase in wollastonite content. The friction coefficient of the PC was getting decreased from 0.457 to 0.198 with an increase in wollastonite content, depending on applied loads and sliding speeds. On the other hand, the results showed that the wear rates of pure PC and wollastonite-filled PCs decreased with an increase in loads. The wear rate of the PC decreased from 1.2 × 10−6 to 8.7 × 10−6 mm3/m with an increase in wollastonite content, depending on applied loads. Originality/value – There are many reports which deal with the friction and wear performance of the polymers and polymer composites. However, the effect of wollastonite effect on tribological performance of PC has up to now not been extensively researched.

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