scholarly journals The Effect of Elemental Composition and Nanostructure of Multilayer Composite Coatings on Their Tribological Properties at Elevated Temperatures

2020 ◽  
Author(s):  
Alexey Vereschaka ◽  
Sergey Grigoriev ◽  
Vladimir Tabakov ◽  
Mars Migranov ◽  
Nikolay Sitnikov ◽  
...  
Keyword(s):  
Elemental Composition ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Elevated Temperatures ◽  
Composite Coatings ◽  
Multilayer Composite ◽  
The Coefficient Of Friction ◽  
The Relationship ◽  
Tribological Parameters ◽  
Adhesion Component

The chapter discusses the tribological properties of samples with multilayer composite nanostructured Ti-TiN-(Ti,Cr,Al,Si)N, Zr-ZrN-(Nb,Zr,Cr,Al)N, and Zr-ZrN-(Zr,Al,Si)N coatings, as well as Ti-TiN-(Ti,Al,Cr)N, with different values of the nanolayer period λ. The relationship between tribological parameters, a temperature varying within a range of 20–1000°C, and λ was investigated. The studies have found that the adhesion component of the coefficient of friction (COF) varies nonlinearly with a pronounced extremum depending on temperature. The value of λ has a noticeable influence on the tribological properties of the coatings, and the nature of the mentioned influence depends on temperature. The tests found that for the coatings with all studied values of λ, an increase in temperature first caused an increase and then a decrease in COF.

Experimental study on the relationship between the friction coefficient and interference in locomotive axle press-fitting

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ting Wang ◽  
Hanfei Guo ◽  
Jianjun Qiao ◽  
Xiaoxue Liu ◽  
Zhixin Fan
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Friction Pair ◽  
Rolling Stock ◽  
Content Type ◽  
Press Fitting ◽  
The Press ◽  
The Coefficient Of Friction ◽  
The Relationship ◽  
Locomotive Wheels

PurposeTo address the lack of data in this field and determine the relationship between the coefficient of friction and the interference between locomotive wheels and axles, this study evaluates the theoretical relationship between the coefficient of friction and the interference under elastic deformation.Design/methodology/approachWhen using numerical analyses to study the mechanical state of the contacting components of the wheels and axle, the interference between the axle parts and the coefficient of friction between the axle parts are two important influencing factors. Currently, as the range of the coefficient of friction between the wheel and axle in interference remains unknown, it is generally considered that the coefficient of friction is only related to the materials of the friction pair; the relationship between the interference and the coefficient of friction is often neglected.FindingsA total of 520 press-fitting experiments were conducted for 130 sets of wheels and axles of the HXD2 locomotive with 4 types of interferences, in order to obtain the relationship between the coefficient of friction between the locomotive wheel and axle and the amount of interference. These results are expected to serve as a reference for selecting the coefficient of friction when designing axle structures with the rolling stock, research on the press-fitting process and evaluations of the fatigue life.Originality/valueThe study provides a basis for the selection of friction coefficient and interference amount in the design of locomotive wheels and axles.

Investigation of the causes of damage to freight cars during disbanding on non-mechanized sorting slides and development of measures to prevent them

2021 ◽  
pp. 4-13
Author(s):  
S. V. Tankeev ◽  
◽  
A. E. Kolodin ◽  
V. B. Sverdlov ◽  
A. V. Nazarov ◽  
...  
Keyword(s):  
Low Power ◽  
Coefficient Of Friction ◽  
Damage Assessment ◽  
Laboratory Tests ◽  
Rolling Stock ◽  
Third Body ◽  
Normative Documents ◽  
The Coefficient Of Friction ◽  
Loading And Unloading ◽  
The Relationship

The damage assessment of freight cars during shunting and loading and unloading operations was made. The need to review the normative documents regulating the relationship between the owners of rolling stock, owners of non-public tracks and the carrier is noted. The reasons for formation of damage on the wheel pairs of freight cars when disbanding on low-power sorting slides are considered. The conditions for ensuring the deceleration of detachments on non-mechanized sorting slides without damaging the wheels are determined. The analysis of methods for ensuring braking on low-power slides is carried out. A method was chosen to ensure the wheel set rotation by introducing a third body between the rubbing surfaces during the braking of cars, which will take over a part of the resulting heat flow, reducing the temperature and increasing the coefficient of friction in the «wheel-rail» contact zone. A method is proposed to provide braking on the non-mechanized sorting slide during shoe braking by applying a friction compound to a non-working rail. Laboratory tests were carried out, which showed that the introduction of a friction additive can achieve the necessary coefficient of friction to comply with the standard parameters of deceleration of the car in the braking zone.

Tribological Properties of Polyoxymethylene Composites Against Aluminum

2003 ◽  
Vol 125 (3) ◽  
pp. 661-669 ◽  
Author(s):  
Masaya Kurokawa ◽  
Yoshitaka Uchiyama ◽  
Tomoaki Iwai ◽  
Susumu Nagai
Keyword(s):  
Wear Rate ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
High Surface ◽  
Surface Hardness ◽  
Disk Surface ◽  
Optical Microscope ◽  
Transfer Film ◽  
The Other ◽  
The Coefficient Of Friction

Tribological properties of several kinds of polyoxymethylene (POM) composites were evaluated for the purpose of developing a polymeric tribomaterial especially suited for mating with aluminum parts having low surface hardness. POM composites containing small amounts of silicon carbide (SiC), POM/SiC; those containing a small amount of calcium octacosanonoate besides SiC, POM/SiC/Ca-OCA; and the one blended with 24 wt % of polytetrafluoroethylene, POM/PTFE(24); were injection-molded into pin specimens and their tribological properties were tested by means of a pin-on-disk type wear apparatus using an aluminum (A5056) mating disk in comparison with a 303 stainless steel (SUS303) disk. Evaluation was focused on observation of the sliding surfaces of the pin specimens and the mating disks by a scanning electron microscope and an optical microscope together with the measurement of surface roughness. In the case of mating against a SUS303 disk having high surface hardness, all pin specimens did not roughen the disk surfaces even after long time of rubbing. Only POM/PTFE(24) composite obviously made a transfer film on the disk surface, while the other composites made an extremely thin one on it. POM/SiC(0.1)/Ca-OCA(1) composite, containing SiC 0.1 wt. % and Ca-OCA 1 wt. %, was found to show the lowest coefficient of friction and the lowest wear rate forming extremely thin transfer film on the mating disk. On the other hand, against an A5056 disk which has lower surface hardness than that of SUS303 disk, unfilled POM and POM composites except POM/SiC(0.1)/Ca-OCA(1) composite roughened the disk surfaces. However, the sliding surface of the A5056 disk rubbed with POM/SiC(0.1)/Ca-OCA(1) composite was significantly smoother and that of the pin specimen was also quite smooth in comparison with other pin specimens. Further, when each POM composite was rubbed against the A5056 disk, formation of transfer film was not obvious on the disk surfaces. For POM/SiC(0.1)/Ca-OCA(1) composite, the wear rate was the lowest of all POM composites, and the coefficient of friction was as low level as 60 percent of that of unfilled POM, but slightly higher than that of POM/PTFE(24) composite. For POM/SiC(0.1)/Ca-OCA(1) composite, the nucleating effect of SiC and Ca-OCA, which accelerated the crystallization of POM during its injection molding to form a matrix containing fine spherulites, must have resulted in increasing the toughness of the matrix and lowering the wear rate. Also, the lubricant effect of Ca-OCA should have lowered the coefficient of friction of the same matrix for rubbing against aluminum mating disk. POM/SiC(0.1)/Ca-OCA(1) composite was concluded as an excellent tribomaterial for mating with aluminum parts.

Some Tribological Properties of an Ionic Liquid

2005 ◽  
Author(s):  
Takashi Nogi
Keyword(s):  
Ionic Liquid ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Friction And Wear ◽  
Wear Performance ◽  
Lubrication Regime ◽  
Pin On Disc ◽  
The Coefficient Of Friction

Some tribological properties of an ionic liquid were investigated by using a pin-on-disc friction and wear tester. Due to running-in, the coefficient of friction of the ionic liquid decreased with time to a very low value of 0.02 which suggests that the lubrication regime was hydrodynamic at the end of the tests. Anti-wear performance of the ionic liquid was substantially comparable to a paraffin-based oil.

Prediction of the Coefficient of Friction for Pneumatic Tyres on Hard Pavement

1975 ◽  
Vol 189 (1) ◽  
pp. 259-266
Author(s):  
Shri Kant ◽  
D. L. Prasanna Rao ◽  
M. L. Munjal
Keyword(s):  
Coefficient Of Friction ◽  
Vertical Load ◽  
Contact Patch ◽  
The Coefficient Of Friction ◽  
The Relationship

The relationship between the coefficient of friction and the slip of a flexible wheel, such as the pneumatic tyre, plays a major role in the design of refined braking systems for vehicles. The available data being partly empirical in nature, it was desirable to be able to predict this relationship. In this paper an attempt is made to explain the mechanism defining this relationship for a pneumatic tyre operating on a hard pavement. The distinct roles of the flexibility of the tyre and the sliding of the wheel are identified and utilized in predicting the curve. A model of the tyre is proposed to explain the role of flexibility of the tyre. It is shown that the procedure suggested here can clearly bring out the effects of some of the operating paramenters of the vehicle, such as speed of the vehicle, presence of contaminants in the contact patch, stiffness of the tyre, and vertical load on the wheel.

Measurement of Tribological Parameters

2014 ◽  
Vol 875-877 ◽  
pp. 496-499 ◽  
Author(s):  
Eva Labašová ◽  
Rastislav Ďuriš
Keyword(s):  
Coefficient Of Friction ◽  
Test Equipment ◽  
Tribological Characteristics ◽  
Sliding Speed ◽  
Sliding Joint ◽  
The Coefficient Of Friction ◽  
Run Up ◽  
Tribological Parameters

The contribution deals with measurement of the coefficient of friction in the sliding joint. Rotanional sliding pair, which was tested, is described in this paper. Their tribological characteristics were measured by test equipment Tribotestor`89. The value of the coefficient of friction for the bushings from brass, aluminium and polyamide for chosen load (the sliding speed, loading, duration) are analysed in the paper. The largest decrease in the size of the coefficient of friction was recorded for bushings from aluminium, its value have decreased by 87.5% during the run up. Decrease of the coefficient of friction was recorded about 82% for bushings from brass and about 72% for bushings from polyamide. Run up lasted 10 minutes in all tests.

THE INFLUENCE OF GLASSY CARBON AND ITS FORMS ON TRIBOLOGICAL PROPERTIES OF ALUMINIUM MATRIX COMPOSITES

Tribologia ◽  
2019 ◽  
Vol 285 (3) ◽  
pp. 79-87 ◽  
Author(s):  
Jerzy MYALSKI ◽  
Andrzej Posmyk ◽  
Bartosz HEKNER ◽  
Marcin GODZIERZ
Keyword(s):  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Glassy Carbon ◽  
Amorphous Structure ◽  
Matrix Composites ◽  
Alloy Matrix ◽  
Entire Volume ◽  
Carbon Particles ◽  
The Matrix ◽  
The Coefficient Of Friction

Carbon with an amorphous structure was used as a component to modify the tribological properties of engineering plastics. Its construction allows the formation of carbon-based wear products during friction, adhesively bonded to the surface of cooperating machine parts, acting as a solid lubricant. The work compares the tribological properties of two groups of composites with an aluminium alloy matrix in which glassy carbon appeared in the form of particles and an open cell foam fulfilling the role of strengthening the matrix. The use of spatial structures of reinforcement provides, in comparison with the strengthening of particles, homogeneity of carbon distribution in the entire volume of the composite. The tests carried out on a pin-disc tester showed that the use of spatial carbon structures in the composite ensures a greater coefficient of friction stability than when reinforcing with particles, and the coefficient of friction with a small proportion of carbon foams (about 1 wt%) is comparable with the coefficient of friction in the contact with composites containing 5-10% carbon particles in granular form.

A Contribution to the Theory of Friction and Wear and the Relationship between them

1976 ◽  
Vol 190 (1) ◽  
pp. 477-488 ◽  
Author(s):  
J. Halling
Keyword(s):  
Shear Stress ◽  
Coefficient Of Friction ◽  
Interfacial Shear Stress ◽  
Failure Criteria ◽  
Elastic Behaviour ◽  
Total Load ◽  
Perfectly Plastic ◽  
The Coefficient Of Friction ◽  
Wear Law ◽  
The Relationship

The nature of the interaction between a rigid spherical asperity and an asperity governed by the stress/strain law [Formula: see text] is studied. The interfacial shear stress is defined by f τmax where 0 < f < 1, τ maxbeing the maximum allowable shear stress at the contact. By integrating the total effect of a population of such surface asperities expressions for the total frictional forces, and the total load are derived. The value of the coefficient of friction is thus obtained and the special conditions for perfectly plastic and elastic behaviour are considered. In both cases the friction coefficient is seen to contain a term defined by the deformation and dependent on surface roughness and a term totally defined by f. Using the same model a fatigue type failure criteria is introduced to predict the volume of wear. It is then possible to produce a wear law which is consistent with experience and which includes the relationship between the wear and the coefficient of friction.

Development of Antifriction Materials Based on Polytetrafluoroethylene with Carbon Fibers and Tungsten Disulfide

2020 ◽  
Vol 992 ◽  
pp. 745-750
Author(s):  
A.P. Vasilev ◽  
T.S. Struchkova ◽  
A.G. Alekseev
Keyword(s):  
Wear Resistance ◽  
Polymer Composites ◽  
Carbon Fibers ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Relative Elongation ◽  
Tungsten Disulfide ◽  
Degree Of Crystallinity ◽  
Mechanical And Tribological Properties ◽  
The Coefficient Of Friction

This paper presents the results from the investigation of effect the carbon fibers with tungsten disulfide on the mechanical and tribological properties of PTFE. Is carried out a comparison of mechanical and tribological properties of polymer composites PTFE-based with carbon fibers and PTFE with complex filler (carbon fibers with tungsten disulfide). It is shown that at a content of 8 wt.% CF+1 wt.% WS2 in PTFE, wear resistance increases significantly while maintaining the tensile strength, relative elongation at break and low coefficient of friction at the level of initial PTFE. The results of X-ray analysis and investigation of SEM supramolecular structure and friction surfaces of PTFE and polymer composites are presented. It is shown that the degree of crystallinity of polymer composites increases in comparison with the initial PTFE. The images of scanning electron microscope reveal that particles of tungsten disulfide concentrating on the friction surface is likely responsible to a reduction in the coefficient of friction and increase the wear resistance of PTFE-based polymer composites with complex fillers.

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