scholarly journals Pin-on-disc study of dry sliding behavior of Co-free HVOF-coated disc tested against different friction materials

Friction ◽  
2021 ◽  
Author(s):  
Matteo Federici ◽  
Cinzia Menapace ◽  
Alessandro Mancini ◽  
Giovanni Straffelini ◽  
Stefano Gialanella

AbstractThe dry sliding behavior of three commercial friction materials (codenamed FM1, FM2, and FM3) tested against a Co-free cermet coating produced by high-velocity oxy-fuel (HVOF) on gray cast-iron discs is investigated. FM1 is a conventional low-metallic friction material, FM2 is developed for using against HVOF-coated discs, and FM3 is a Cu-free friction material with a low content of abrasives and a relatively high concentration of steel fibers. For the tribological evaluation, they are tested on a pin-on-disc (PoD) test rig against Co-free HVOF-coated discs, with particular attention to the running-in stage, which is fundamental for the establishment of a friction layer between the two mating surfaces, i.e., the pin and disc. The PoD tests are performed at room temperature (RT) and a high temperature (HT) of 300 °C. At RT, all materials exhibit a long running-in stage. At HT, no running-in is observed in FM1 and FM2, whereas a shorter running-in period, with respect to the RT case, is observed in FM3 followed by the attainment of a comparatively high coefficient of friction. At RT, the pin wear is mild in all cases but severe at HT. FM3 shows the lowest wear rate at both temperatures. Moreover, the coated disc shows no wear when sliding against the FM3 friction material. All the results are interpreted considering the microstructural characteristics of the friction layers formed on the sliding surfaces. The findings of the present study provide insights into reducing wear in braking system components and hence reducing environmental particulate matter emissions from their wear, through the use of disc coatings.

2017 ◽  
Vol 115 ◽  
pp. 89-99 ◽  
Author(s):  
Matteo Federici ◽  
Cinzia Menapace ◽  
Alessandro Moscatelli ◽  
Stefano Gialanella ◽  
Giovanni Straffelini

2020 ◽  
Vol 21 (6) ◽  
pp. 613
Author(s):  
Amira Sellami ◽  
Nesrine Hentati ◽  
Mohamed Kchaou ◽  
Mohammad Asaduzzaman Chowdhury ◽  
Riadh Elleuch

Friction materials are composed of numerous ingredients which differ from nature and particles size. Each ingredient has its own impact on the mechanical and tribological behavior of the material. Brass ingredients have a great impact on the thermal gradient dissipation in the sliding contact between disc and brake pad material. In this research, the influence of different sizes and forms of brass ingredient was studied on the friction material behavior. The physical (density), mechanical (yield strength, young module) and thermal (thermal conductivity and specific heat) properties of the considered composites were characterized. Results proves that only physical and mechanical properties are sensitive to the changes in size and form of brass particles. The tribological behavior of the brake friction materials was also assessed using a pin-on-disc tribometer. The results show that bigger brass particles and their elongated shape allows it to be well embedded on the pad surface during braking application, and thus decreased wear rate . In contrast, the smaller particle decrease the friction stability and it rounded shape increase wear of the material since it tearing from the surface by abrasive wear.


2018 ◽  
Vol 119 ◽  
pp. 73-81 ◽  
Author(s):  
Mara Leonardi ◽  
Cinzia Menapace ◽  
Vlastimil Matějka ◽  
Stefano Gialanella ◽  
Giovanni Straffelini

Wear ◽  
2020 ◽  
Vol 442-443 ◽  
pp. 203157 ◽  
Author(s):  
Mara Leonardi ◽  
Mattia Alemani ◽  
Giovanni Straffelini ◽  
Stefano Gialanella

2021 ◽  
Vol 871 ◽  
pp. 170-175
Author(s):  
Hao Li ◽  
Bo He

To prepare a kind of Fe-Cu-based friction material with good friction performance and wear resistance, and apply it to the brake structure of automobile machinery, the powder metallurgy method is used to prepare the friction materials in the standard with 4% Ni, 4% Mo and 2% Sn as the auxiliary material, SiC, Al2O3, and zircon sand as the basic friction material, 8% graphite and 3% MoS2 as the lubricating component. Meanwhile, 50% Fe and 20% Cu is used for the preparation of friction materials. The friction and wear resistance can be increased by increasing the carbon fiber content of 0-8% concentration of the material. The results show that the friction coefficient of the Fe-Cu-based friction material is relatively gentle after the addition of 2% carbon fiber, and the compactness peaks, reaching 93.3%. Its shear strength and impact strength peak, which are 37.42Mpa and 6.7J/cm2 respectively. 4% carbon fiber material with a hardness of 120.2 HV is the hardest one, followed by 2% carbon fiber material with a hardness of 118.1 HV. Added with 2% carbon fiber, the abrasion amount of the friction-based material is 0.0027 g at room temperature and-0.0008 g at 400°C after 60 minutes respectively. With all indicators considered, the result shows that the friction performance and wear resistance of Fe-Cu-based friction materials can be increased by adding 2% carbon fiber during the preparation of basic friction materials.


Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3281
Author(s):  
Chiara Soffritti ◽  
Annalisa Fortini ◽  
Anna Nastruzzi ◽  
Ramona Sola ◽  
Mattia Merlin ◽  
...  

This work evaluates the dry sliding behavior of anodic aluminum oxides (AAO) formed during one traditional hard anodizing treatment (HA) and two golden hard anodizing treatments (named G and GP, respectively) on a EN AW-6060 aluminum alloy. Three different thicknesses of AAO layers were selected: 25, 50, and 100 μm. Prior to wear tests, microstructure and mechanical properties were determined by scanning electron microscopy (VPSEM/EDS), X-ray diffractometry, diffuse reflectance infrared Fourier transform (DRIFT-FTIR) spectroscopy, roughness, microhardness, and scratch tests. Wear tests were carried out by a pin-on-disc tribometer using a steel disc as the counterpart material. The friction coefficient was provided by the equipment. Anodized pins were weighed before and after tests to assess the wear rate. Worn surfaces were analyzed by VPSEM/EDS and DRITF-FTIR. Based on the results, the GP-treated surfaces with a thickness of 50 μm exhibit the lowest friction coefficients and wear rates. In any case, a tribofilm is observed on the wear tracks. During sliding, its detachment leads to delamination of the underlying anodic aluminum oxides and to abrasion of the aluminum substrate. Finally, the best tribological performance of G- and GP-treated surfaces may be related to the existence of a thin Ag-rich film at the coating/aluminum substrate interfaces.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Qianqian Sheng ◽  
Min Song ◽  
Zunling Zhu ◽  
Fuliang Cao

AbstractCarpinus betulus and Carpinus putoensis are precious species in the world. Studies on the ecosystem function of the two species are rare. This study investigated the physiological and biochemical responses of C. betulus and C. putoensis to NO2 stress and their natural recovery. C. betulus and C. putoensis seedlings underwent fumigation with 12.0 mg/m3 NO2 for 0, 1, 6, 12, 24, 48, and 72 h, respectively. Then, the plants were allowed to recover at room temperature for 30 d. Physiological and biochemical changes in the leaves were compared between the two species. In terms of peroxidase (POD) activity, the damage response of C. betulus under NO2 stress appeared later than that of C. putoensis. The soluble protein content of C. betulus was noticeably higher than that of C. putoensis, and C. betulus exhibited more stable membrane lipoperoxidation. The tendency of the changes in nitrate reductase of C. betulus was less noticeable than that of C. putoensis. The variation amplitudes of N, K, Mg, Zn and Mn in the leaves of C. putoensis were greater than those of C. betulus. C. putoensis showed more sensitive metabolisms in response to NO2 stress compared with C. betulus. High-concentration NO2 caused damage to C. betulus and C. putoensis was reversible, and both species returned to normal growth via their own metabolism after 30-d recovery. The results of this study may provide useful reference data for quantitative assessment of the ecosystem function of C. betulus and C. putoensis and for their scientific application in urban greening.


2010 ◽  
Vol 31 (3) ◽  
pp. 1526-1532 ◽  
Author(s):  
G. Naveen Kumar ◽  
R. Narayanasamy ◽  
S. Natarajan ◽  
S.P. Kumaresh Babu ◽  
K. Sivaprasad ◽  
...  

2018 ◽  
Vol 1150 ◽  
pp. 22-42
Author(s):  
Dinesh Shinde ◽  
Kishore N. Mistry ◽  
Suyog Jhavar ◽  
Sunil Pathak

The peculiar feature of friction materials to absorb the kinetic energy of rotating wheels of an automobile to control the speed makes them remarkable in automobile field. The regulation of speed cannot be achieved with the use of single phase material as a friction material. Consequently, the friction material should be comprised of composite materials which consist of several ingredients. Incidentally, the friction materials were formulated with friction modifier, binders, fillers and reinforcements. Due to its pleasant physical properties, asbestos was being used as a filler. Past few decades, it is found that asbestos causes dangerous cancer to its inhaler, which provides a scope its replacement. Several attempts have been made to find an alternative to the hazardous asbestos. The efforts made by different researchers for the impact of every composition of composite friction material in the field are reviewed and studied for their effect on the properties of friction material. Surface morphological studies of different friction material are compared to interpret the concept of surface wear and its correlation with material properties.


2014 ◽  
Vol 592-594 ◽  
pp. 1305-1309 ◽  
Author(s):  
K. Rajkumar ◽  
S. Aravindan

Effects of graphite content, and sliding speed on the tribological characteristics of copper-graphite composites under dry sliding condition were evaluated using a pin-on-disc tribometer. The worn surfaces of the composites were analyzed through Scanning Electron Microscopy (SEM). The experimental results revealed the improvement in wear resistance with increasing graphite content. The friction coefficient is also gradually decreasing upto 25 vol% graphite. Sliding speed has an effect on copper (5-15 vol%) graphite composites where as sliding speed has no effect in copper-(20-30 vol%) graphite composites. This difference is attributed to availability of self-lubricating graphite layer at the contact zone.


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