The Performance Of Semi–Metallic Friction Materials For Passenger Cars

2012 ◽  
Author(s):  
Ria Jaafar Talib ◽  
Andanastuti Muchtar ◽  
Che Husna Azhari
Keyword(s):  
Steady State ◽  
Friction Coefficient ◽  
Surface Temperature ◽  
Wear Mechanism ◽  
Morphological Changes ◽  
Wear Behaviour ◽  
Wear Volume ◽  
Brake Disc ◽  
Passenger Cars ◽  
Metallic Friction

Dalam kajian ini, penilaian haus mekanikal ke atas bahan geseran separa logam untuk kegunaan kereta penumpang dikaji dengan menekan sampel kepada piring yang berpusing diperbuat daripada besi tuang kelabu pearlitik. Bagi setiap ujian, sampel dikenakan empat jangka masa pembrekan (3, 6, 9, dan 12 minit) dan empat beban kenaan (200, 400, 600 dan 800 N) yang berlainan. Kelajuan putaran piring brek dikekalkan malar sepanjang pengujian geseran pada 750 psm. Selepas setiap ujian, perubahan morfologi permukaan dan subpermukaan diperhatikan dengan menggunakan mikroskop elektron imbasan (MEI). Hasil kajian menunjukkan ciri-ciri berikut: (i) suhu permukaan meningkat dengan masa pembrekan dan selepas mencapai nilai maksimum, akhirnya sampai kepada keadaan stabil, (ii) pekali geseran telah meningkat pada permulaan pembrekan, kemudian menurun dengan masa pembrekan, dan seterusnya sampai kepada keadaan stabil, dan (iii) isipadu haus meningkat secara lelurus apabila beban kenaan di bawah 200 N dan/atau masa pembrekan di bawah 3 minit dan kedua-duanya seterusnya meningkat secara eksponen. Pemeriksaan mikrostruktur menunjukkan mekanisme haus beralih dengan peningkatan jangka masa pembrekan dan beban kenaan. Fenomena ini juga menyebabkan perubahan kepada sifat haus. Kata kunci: Pad brek, suhu permukaan, pekali geseran, haus, mekanisme haus In this work, a semi-metallic friction material for passenger cars was evaluated for mechanical wear by pressing the material against a rotating pearlitic gray cast iron brake disc. In each test, the sample was subjected to four different braking times (3, 6, 9, and 12 minutes) and four applied loads (200, 400, 600 and 800 N). The rotating velocity of the disc was kept constant throughout the friction tests at 750 rpm. After each test, the morphological changes on the surface and subsurface of the material were observed using Scanning Electron Microscopy (SEM). The following characteristics were observed: (i) the surface temperature increased with braking time and after reaching a maximum value, eventually arrived at a steady state, (ii) the friction coefficient increased at the early stages of braking, then decreased with braking time and thereafter reached steady state, and (iii) the wear volume increased linearly when the applied load was below 200 N and/or braking time was below 3 minutes or both, thereafter the volume increased exponentially. Microstructural examinations showed that the wear mechanism transisted with increase in braking times as well as applied loads. This phenomenon also resulted in changes of the wear behaviour. Key words: Brake pad, surface temperature, friction coefficient, wear, wear mechanism

Effect of Graphite Content on Cu–Ni–Graphite Composite for Use as Switch Slide Baseplate Materials Sliding Against U75V Steel

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Yiran Wang ◽  
Yimin Gao ◽  
Jun Takahashi ◽  
Yi Wan ◽  
Yunqian Zhang ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Wear Mechanism ◽  
High Speed ◽  
Sliding Friction ◽  
Rapid Development ◽  
Wear Volume ◽  
Fatigue Wear ◽  
Friction Coefficients ◽  
Graphite Composite ◽  
Graphite Content

Abstract The rapid development of high-speed railways necessitates the development of new materials for switch slide baseplates. In this study, a Cu–Ni–graphite composite, containing 1 wt% to 6 wt% graphite and prepared by powder metallurgy, was used as a potential material. Pin-on-disk wear tests were conducted to measure the sliding friction of the Cu–Ni–graphite composite against U75 V steel. The results showed that the friction coefficients gradually decreased when the graphite content in the composite ranged from 1 wt% to 4 wt% in the composite. When the graphite content was 4 wt%, the friction coefficient reached the minimum value (0.153). When the graphite content was low (1 wt% to 4 wt%), the primary wear mechanism was microcutting. An increased graphite content facilitated the generation of lubricating films and decreased the wear damage. As the graphite content increased from 4 wt% to 6 wt%, the friction coefficients also increased. The variation in the wear volume rate had the same tendency as the friction coefficient. When the graphite content exceeded 4 wt%, the primary wear mechanism was delamination and fatigue wear. Due to the tendency to form cracks on the subsurface and the plentiful generation of the spalled pits, the graphite fragments could not completely form lubricating films but separated as wear debris. The lubricating films existing on the U75 V steel were in proportion to the graphite content in the composite. The wear weight loss of the U75 V steel exhibited a reduction with increasing graphite content.

Study on Fretting Wear Behavior of 40CrNiMoA Steel

2010 ◽  
Vol 139-141 ◽  
pp. 447-451
Author(s):  
Zhu Jun Li
Keyword(s):  
Friction Coefficient ◽  
Abrasive Wear ◽  
Wear Mechanism ◽  
Wear Behavior ◽  
Experimental Results ◽  
Fretting Wear ◽  
Wear Volume ◽  
Volume Increase ◽  
Test Parameters ◽  
Adhesion Wear

This study deals with fretting wear behavior of 40CrNiMoA steel on a SRVⅣoscillating friction and wear tester. The results indicate that with the frequency and load increasing, both the friction coefficient and fretting wear volume increase. With the amplitude increasing, the fretting wear volume increased too, but the effect of amplitude on friction coefficient was not simple positive correlation according to the experimental results. Meanwhile, the fretting wear mechanism is directly related to test frequency, load and amplitude. When they are small, the main fretting wear mechanism is abrasive wear, with these test parameters increasing, the main fretting wear mechanism turns to a combination of abrasive wear and adhesion wear. Based on the experimental results, the anti-fretting wear measures of steel worm gear pairs used in mechanical tracked regulator of tracked vehicle are discussed.

scholarly journals Wear Behaviour and Friction Property of SiCp/Al Composites at Elevated Wear Environment Temperature

2002 ◽  
Vol 11 (6) ◽  
pp. 096369350201100 ◽  
Author(s):  
JJ Ahn ◽  
S. Ochiai
Keyword(s):  
Friction Coefficient ◽  
Abrasive Wear ◽  
Wear Mechanism ◽  
Point Contact ◽  
Wear Behaviour ◽  
Sliding Speed ◽  
Sic Particles ◽  
Environment Temperature ◽  
Worn Surface ◽  
Worn Surfaces

The effects of sliding speed and wear environment temperature (hereafter denoted as temperature) on the wear behaviour and friction coefficient of SiC particle reinforced A16061 composites (SiCp/Al) were studied using wear and friction test of a ring on disc type, and difference of wear mechanism in terms of temperature was also examined by a microscopic observation of worn surfaces. Thin surface layer (TSL) formed on the worn surface during the experiment was enhanced with increase of temperature. However, such a TSL was cracked due to point contact between the counter material and coarse SiC particles (and/or SiC clusters) existing on the worn surface of the SiCp/Al. Contour of worn surfaces became rougher with increase of temperature and sliding speed. Wear mechanism of the AA6061 changed from abrasive wear into adhesive wear at 300°C while for the SiCp/Al, wear mechanism did not changed in the test conditions. That is, abrasive wear was maintained up to 300°C. Due to the presence of SiC particles, Friction coefficient of the SiCp/Al was larger than that of the AA6061 regardless of the temperature. However, scatter of friction coefficient against temperature was smaller in the SiCp/Al than in the AA6061. Furthermore, the weight loss, the difference of specimen weight before and after the experiment, under the severest test condition was less in the SiCp/Al than in the AA6061.

Tribological characterization of all-polymer prosthesis based on multi-directional motion

2021 ◽  
pp. 089270572110286
Author(s):  
Xinyue Zhang ◽  
Dekun Zhang ◽  
Kai Chen ◽  
Handong Xu ◽  
Cunao Feng
Keyword(s):  
Friction Coefficient ◽  
Abrasive Wear ◽  
Wear Mechanism ◽  
Friction And Wear ◽  
Quantitative Relationship ◽  
Motion Path ◽  
Aspect Ratios ◽  
Directional Motion ◽  
Motion Paths ◽  
Prosthesis Material

The complex movement of artificial joints is closely related to the wear mechanism of the prosthesis material, especially for the polymer prosthesis, which is sensitive to motion paths. In this paper, the “soft-soft” all-polymer of XLPE/PEEK are selected to study the influence of motion paths on the friction and wear performance. Based on the periodic characteristics of friction coefficient and wear morphology, this paper reveals the friction and wear mechanism of XLPE/peek under multi-directional motion path, and obtains the quantitative relationship between friction coefficient and the aspect ratios of “∞”-shape motion path, which is of great significance to reveal and analyze the wear mechanism of “soft” all-polymer under multi-directional motion path. The results show that the friction coefficient is affected by the motion paths and have periodicity. Morever, under the multi-directional motion paths, the wear of PEEK are mainly abrasive wear and adhesive wear due to the cross shear effect, while the wear of XLPE is mainly abrasive wear with plastic accumulation. In addition, the friction coefficient is greatly affected the aspect ratios Rs-l of “∞”-shape and loads. Meanwhile, the wear morphologies are greatly affected by the aspect ratios Rs-l of “∞”-shape, but less affected by loads.

scholarly journals The Effect of Co-Deposition of SiC Sub-Micron Particles and Heat Treatment on Wear Behaviour of Ni–P Coatings

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 180
Author(s):  
Donya Ahmadkhaniha ◽  
Lucia Lattanzi ◽  
Fabio Bonora ◽  
Annalisa Fortini ◽  
Mattia Merlin ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Friction Coefficient ◽  
Wear Mechanisms ◽  
Composite Coatings ◽  
Wear Behaviour ◽  
Maximum Hardness ◽  
Sic Particles ◽  
Heat Treated ◽  
The Coefficient Of Friction ◽  
The Difference

The purpose of the study is to assess the influence of SiC particles and heat treatment on the wear behaviour of Ni–P coatings when in contact with a 100Cr6 steel. Addition of reinforcing particles and heat treatment are two common methods to increase Ni–P hardness. Ball-on-disc wear tests coupled with SEM investigations were used to compare as-plated and heat-treated coatings, both pure and composite ones, and to evaluate the wear mechanisms. In the as-plated coatings, the presence of SiC particles determined higher friction coefficient and wear rate than the pure Ni–P coatings, despite the limited increase in hardness, of about 15%. The effect of SiC particles was shown in combination with heat treatment. The maximum hardness in pure Ni–P coating was achieved by heating at 400 °C for 1 h while for composite coatings heating for 2 h at 360 °C was sufficient to obtain the maximum hardness. The difference between the friction coefficient of composite and pure coatings was disclosed by heating at 300 °C for 2 h. In other cases, the coefficient of friction (COF) stabilised at similar values. The wear mechanisms involved were mainly abrasion and tribo-oxidation, with the formation of lubricant Fe oxides produced at the counterpart.

Wear Behaviour of TiC Coated AISI 4340 Steel Produced by TIG Surface Melting

2015 ◽  
Vol 819 ◽  
pp. 76-80 ◽  
Author(s):  
Md Abdul Maleque ◽  
Belal Ahmed Ghazal ◽  
Mohammad Yeakub Ali ◽  
Maan Hayyan ◽  
Abu Saleh Ahmed
Keyword(s):  
Plastic Deformation ◽  
Wear Resistance ◽  
Steel Surface ◽  
Composite Layer ◽  
Wear Behaviour ◽  
Wear Volume ◽  
Coated Steel ◽  
Aisi 4340 Steel ◽  
4340 Steel ◽  
Aisi 4340

Coating possesses superior wear resistance which makes the material suitable for components subjected to dynamic applications under sever wearing condition and high temperature applications. In this study, TiC coating layer was synthesized by preplacing a 1 mg/mm2of fine size (~40 μm) TiC powder on the surface of AISI 4340 steel. The composite layer was produced by rapidly melting TiC powder together with the substrate steel using tungsten inert gas (TIG) torch welding at a fixed heat input of 1344 J/mm. The wear behaviour of the coated steel was investigated using a universal pin-on-disc tribometer. The microhardness profile of the coating showed increment of the hardness value (almost 5 times higher) than the substrate material. The wear test results showed that the TiC coated steel has lower wear volume loss hence, higher wear resistance compared to the substrate AISI 4340 steel. Incorporation of TiC into the steel surface has improved the wear behaviour of the steel by reduction of plastic deformation and ploughing of the steel surface. The SEM micrograph of the wear worn surface showed mild type of abrasive wear for coated steel whereas, the AISI 4340 steel showed severe type wear with excessive plastic deformation and ploughing.

scholarly journals An Investigation on Tribological Properties and Lubrication Mechanism of Graphite Nanoparticles as Vegetable Based Oil Additive

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yu Su ◽  
Le Gong ◽  
Dandan Chen
Keyword(s):  
Friction Coefficient ◽  
Tribological Properties ◽  
Volume Fraction ◽  
Wear Volume ◽  
Lubrication Mechanism ◽  
Step Method ◽  
Antiwear Properties ◽  
Physical Deposition ◽  
Graphite Nanoparticles ◽  
Friction Reducing

This paper used graphite nanoparticles with the diameter of 35 and 80 nm and LB2000 vegetable based oil to prepare graphite oil-based nanofluids with different volume fractions by two-step method. The tribological properties of graphite nanoparticles as LB2000 vegetable based oil additive were investigated with a pin-on-disk friction and wear tester. Field emission scanning electron microscope (FE-SEM) and energy dispersive spectroscopy (EDS) were used to examine the morphology and the content of some typical elements of wear scar, respectively. Further, the lubrication mechanism of graphite nanoparticles was explored. It was found that graphite nanoparticles as vegetable based oil additive could remarkably improve friction-reducing and antiwear properties of pure oil. With the increase of volume fraction of graphite nanoparticles, the friction coefficient and the wear volume of disk decreased. At the same volume fraction, the smaller particles, the lower friction coefficient and wear volume. The main reason for the improvement in friction-reducing and antiwear properties of vegetable based oil using graphite nanoparticles was that graphite nanoparticles could form a physical deposition film on the friction surfaces.

scholarly journals Role of Silicon Dioxide Filler on Mechanical and Dry Sliding Wear Behaviour of Glass-Epoxy Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Naveed Anjum ◽  
S. L. Ajit Prasad ◽  
B. Suresha
Keyword(s):  
Silicon Dioxide ◽  
Sliding Wear ◽  
Wear Behaviour ◽  
Dry Sliding Wear ◽  
Wear Volume ◽  
Dry Sliding ◽  
Scanning Electron Micrographs ◽  
Sliding Velocity ◽  
Sliding Distance ◽  
Sliding Wear Behaviour

The mechanical properties and dry sliding wear behaviour of glass fabric reinforced epoxy (G-E) composite with varying weight percentage of silicon dioxide (SiO2) filler have been studied in the present work. The influence of sliding distance, velocity, and applied normal load on dry sliding wear behaviour has been considered using Taguchi's L9orthogonal array. Addition of SiO2increased the density, hardness, flexural, and impact strengths of G-E composite. Results of dry sliding wear tests showed increasing wear volume with increase in sliding distance, load, and sliding velocity for G-E and SiO2filled G-E composites. Taguchi's results indicate that the sliding distance played a significant role followed by applied load, sliding velocity, and SiO2loading. Scanning electron micrographs of the worn surfaces of composite samples at different test parameters show smooth surface, microploughing, and fine grooves under low load and velocity. However, severe damage of matrix with debonding and fiber breakage was seen at high load and velocity especially in unfilled G-E composite.

Steady-State Investigation of Vapor Deposited Micro Heat Pipe Arrays

1995 ◽  
Vol 117 (1) ◽  
pp. 75-81 ◽  
Author(s):  
A. K. Mallik ◽  
G. P. Peterson
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Surface Temperature ◽  
Heat Pipe ◽  
Effective Thermal Conductivity ◽  
Heat Pipes ◽  
Temperature Gradients ◽  
Bottom Surface ◽  
Micro Heat Pipe ◽  
Micro Heat Pipes

An experimental investigation of vapor deposited micro heat pipe arrays was conducted using arrays of 34 and 66 micro heat pipes occupying 0.75 and 1.45 percent of the cross-sectional area, respectively. The performance of wafers containing the arrays was compared with that of a plain silicon wafer. All of the wafers had 8 × 8 mm thermofoil heaters located on the bottom surface to simulate the active devices in an actual application. The temperature distributions across the wafers were obtained using a Hughes Probeye TVS Infrared Thermal Imaging System and a standard VHS video recorder. For wafers containing arrays of 34 vapor deposited micro heat pipes, the steady-state experimental data indicated a reduction in the maximum surface temperature and temperature gradients of 24.4 and 27.4 percent, respectively, coupled with an improvement in the effective thermal conductivity of 41.7 percent. For wafers containing arrays of 66 vapor deposited micro heat pipes, the corresponding reductions in the surface temperature and temperature gradients were 29.0 and 41.7 percent, respectively, and the effective thermal conductivity increased 47.1 percent, for input heat fluxes of 4.70 W/cm2. The experimental results were compared with the results of a previously developed numerical model, which was shown to predict the temperature distribution with a high degree of accuracy, for wafers both with and without the heat pipe arrays.

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