Effects of Different Types of Crosslinking of Epoxidized Natural Rubber in Semi-Metallic Friction Materials on Friction Performance

2013 ◽  
Vol 686 ◽  
pp. 130-136
Author(s):  
A. Almaslow ◽  
Chantara Thevy Ratnam ◽  
M.J. Ghazali ◽  
R.J. Talib ◽  
C.H. Azhari

Semi-metallic friction composites (SMFC) consist of epoxidised natural rubber with 50 mol % epoxidation (ENR50), alumina nanoparticle, steel wool, graphite and benzoxazine were prepared by melt mixing using Haake internal mixer at 90°C and 60 rpm rotor speed. The composites were vulcanized using different crosslinking systems, namely, sulfur and electron beam (EB) crosslinking. The samples were subjected for friction test in order to determine friction and wear properties of SMFC. The friction–wear properties of the SMFC crosslinked by electron beam irradiation and sulfur vulcanization system were compared. The friction coefficient in normal and hot condition of irradiated SMFC were higher than those of sulphur vulcanized samples at all applied doses. On the other hand the specific wear rates of irradiated samples were lower than the sulfur vulcanized samples at all applied doses. The sample crosslinked by EB irradiation at 150 kGy dose found to exhibit the best tribological property, as evident from the higher friction coefficient (about 0.461) and lower wear achieved at 150 kGy irradiation as compared to sulphur vulcanization of the SMFC.

2017 ◽  
Vol 733 ◽  
pp. 60-64
Author(s):  
Munir Tasdemir ◽  
Ozkan Gulsoy

In the present work, the friction and wear properties of Polypropylene (PP) based composites filled with Hydroxyapatite (HA) particles were studied. Fillers contents in the PP were 10, 20, and 30 wt%. The effects of hydroxyapatite ratio on the water absorption, friction and wear properties of the polymer composites is presented. The result showed that the addition of HA to the composite changed the water absorption, friction coefficient and wear rate.


2016 ◽  
Vol 1133 ◽  
pp. 236-240
Author(s):  
Teku Zakwan Zaeimoedin ◽  
Mazlina Mustafa Kamal ◽  
Ahmad Kifli Che Aziz

In tyre industries, rheological and processability properties of rubber and polymer are great of importance since there are alot extrusion processes involved in the tyre manufacturing other than calendaring and moulding processes. Uniformity and consistency in the flow behaviour and processability of rubber are essential in providing the solution to the rubber industries in order to improve productivity, products quality and energy conservation. In this works, effects of silane coupling agent on rheological behaviour and extrusion performance of silica filled ENR tread compounds were studied and compared to NR/BR tread compound. The compounds were prepared by melt mixing in tangential internal mixer, while the rheological properties of compounds were determined by Capillary Rheometer, Cure Rheometer and Mooney viscometer. The compound were further examined for its extrudability performance evaluation by extruded the rubber through 30mm cold feed extruder machine using ASTM Extrusion Die, ‘Garvey’ type. Results showed that, ENR/silica compounds exhibit higher shear viscosity curves as compared to NR/BR compound at low shear rate regime. However an opposite trend was observed towards high shear rate regime tested which ENR/silica compounds gave slightly lower shear viscosity curve compared to NR/BR compound. As for extrudability performance evaluation, NR/BR compound gave better extrusion characteristics and appearance as compared to ENR/silica compounds.


1992 ◽  
Vol 114 (1) ◽  
pp. 131-140 ◽  
Author(s):  
K. Komvopoulos ◽  
H. Li

The processes of tribofilm formation and disruption and the predominant tribo-mechanisms of unlubricated ceramic materials were investigated experimentally. Sliding experiments in humidity controlled atmospheres revealed that the formation of interfacial tribofilms significantly affects the steady-state friction and wear properties of ceramics. Scanning electron microscopy and various composition analysis techniques demonstrated that although tribochemical reactions might occur, the principal mechanisms of tribofilm formation were the generation, agglomeration, and compaction of fine wear debris produced from both sliding surfaces. The tribofilms exhibited different tribological characteristics, depending on their elemental compositions and the humidity. For all the ceramic pairs tested, the steady-state coefficients of friction decreased with relative humidity. In contrast to the conventional fracture toughness approach, surface profilometry and microscopy studies showed that the highest wear rates were encountered with the toughest ceramic. Plowing grooves parallel to the direction of sliding, fine wear debris of round and cylindrical shapes, microcracking, and localized delamination of the tribofilms were identified. Microscopic observations suggested that damage of the subsurface material adjacent to the interface of the tribofilms was immeasurable. Qualitative comparison of the topographical features of worn surfaces indicated that, depending on the humidity and the type of ceramic, microplasticity, microfracture, and delamination of the tribofilms were the prevailing steady-state tribomechanisms.


2011 ◽  
Vol 311-313 ◽  
pp. 1177-1181 ◽  
Author(s):  
Xing Dong Yuan ◽  
Bin Xu ◽  
Xiao Jie Yang ◽  
Hai Long Ma

The friction and wear properties of Polytetrafluoroethylene (PTFE) coatings before and after gamma irradiation were studied under vacuum conditions. Experimental results indicated that the friction and wear properties of PTFE coatings were improved by gamma irradiation. Results showed that the wear process of PTFE coatings before and after gamma irradiation consists of three stages. The steps for the irradiated PTFE are slightly longer than that for the non-irradiated samples. The friction coefficient of irradiated PTFE coatings reduces slightly compared to that of the non-irradiated samples. The friction coefficients of the PTFE coatings before and after gamma irradiation first increase with the increase of sliding velocity and then decrease with the increase of sliding velocity, and The friction coefficient of PTFE coatings before and after gamma irradiation decreases with the increase of load. The wear of irradiated PTFE coatings is slightly lower than that of non-irradiated PTFE coatings. The wear of PTFE coatings before and after gamma irradiation first decreases with the increase of sliding speed and then increases as the sliding speed increases. The wear of PTFE coatings first decreases with the increase of load and then increases with the increase of load. Scanning electron microscope (SEM) was utilized to investigate the worn surfaces.


2011 ◽  
Vol 175 ◽  
pp. 136-139 ◽  
Author(s):  
Bing Suo Pan ◽  
Xiao Hong Fang ◽  
Ming Yuan Niu

To reduce the friction coefficient between impregnated diamond bit and rock, experiments on addition of graphite to the matrix material of bit cutters were conducted. The cutters were made up of diamond contained working layers and binding layers. The friction and wear properties of cutters and binding layers were investigated using a pin-on-disc friction & wear tester with granite as tribopair. The results showed that with addition of graphite, the hardness and friction coefficient of binding layer decreased, but its wear resistance increased; compared to cutters without graphite, those cutters containing graphite had lower wear loss and friction coefficient and their sliding wear process was much steadier, but diamond protrusion was still normal.


2013 ◽  
Vol 844 ◽  
pp. 109-112 ◽  
Author(s):  
Chesidi Hayichelaeh ◽  
Charoen Nakason ◽  
Anoma Thitithammawong

Epoxidized natural rubber (ENR)/Polypropylene (PP) thermoplastic vulcanizates were prepared by melt mixing method in an internal mixer. Influences of different mixing methods for incorporation of processing oil into the TPVs on tensile and dynamic mechanical properties of the TPVs and crystallinity of the PP were investigated. Results show that distribution of processing oil in the ENR/PP TPV is important due to the processing oil can promote and in the same time can interrupt an improvement in elastomeric properties of the TPV. Incorporation of processing oil into the ENR phase by preparation of oil extended ENR (the mixing method 1) before mixing with the PP was the better way to produce the TPV. It promoted the TPV with superior tensile and dynamic mechanical properties than the TPVs prepared from the mixing method 2 and 3 in which the processing oil was directly added into the PP phase. Furthermore, the TPV from the mixing method 1 had less effect of processing oil on the PP crystallization.


2012 ◽  
Vol 220-223 ◽  
pp. 915-920
Author(s):  
Jeng Haur Horng ◽  
Jen Fin Lin ◽  
Shin Yuh Chern ◽  
Chin Chung Wei ◽  
Chun Yueh Chen

With the rapid development of microelectromechanical systems (MEMS) technology, materials such as silicon, metal, and polymers are widely used in the MEMS field. One of the reliability concerns related to Si MEMS is unwanted wear and adhesion. Therefore, SiC film is a possible choice for surfaces because of its favorable friction and wear properties such as used in cutting tool and transmission system of wind turbine. In this study, biocompatible SAM film (ODS) was used to decrease the adhesion force and the friction coefficient of SiC surface. Experimental results show that ODS can increase the contact angle and decrease the surface roughness value of SiC surfaces for the different roughness values and roughness directions. For Si, SiC film and SAMs film on surfaces, larger normal forces lead to smaller friction coefficients and cross roughness pattern have a smaller friction coefficient than that of straight roughness pattern. In addition, ODS film can decrease the friction coefficient on cross topography with relative small roughness value more effectively than can straight topography of SiC surfaces.


2018 ◽  
Vol 913 ◽  
pp. 205-211
Author(s):  
Dong Mei Liu ◽  
Qiang Song Wang ◽  
Wei Yuan ◽  
Xu Jun Mi

A comparative study on the friction and wear properties of three kinds of copper alloys, including Cu-Ni based, Cu-Al and Cu-Be alloys was carried out in this study. The friction pair was stainless steel, and both dry and MoS2 lubrication friction experiments were investigated. During the experiments, different loads were chosen for different alloys. It was found that under dry friction condition, the friction coefficients of both Cu-Ni based and Cu-Al alloys did not change as the loads changes, whereas the friction coefficient of Cu-Be alloy increased as the loads increases. Under lubrication friction condition, the friction coefficients of all three alloys did not change as the load changes. The results show that the dry friction coefficient of Cu-Ni based alloy was the largest (0.74), the Cu-Al alloy next (0.60), and the Cu-Be alloy had the smallest dry friction coefficient (0.54). The lubrication friction coefficient of Cu-Ni based and Cu-Be was equal and relatively smaller (0.12), whereas the Cu-Al alloy had a relative larger lubrication friction coefficient (0.27). The microstructure observations were consistent with the friction and wear performance, and the SEM results show that different wear mechanisms were dominated for different alloys.


2012 ◽  
Vol 538-541 ◽  
pp. 1920-1923
Author(s):  
Yu Lin Qiao ◽  
Shan Lin Yang ◽  
Yan Zang ◽  
Xin Yu Dong ◽  
Qing Sheng Cui

The friction and wear properties of GCr15/45# steel frictional pairs lubricated by n- Al2O3 additives under ultrasonic vibration or not were studied. The scanning electron microscope(SEM), X-ray photoelectron spectroscopy(XPS) and energy dispersive spectrometer (EDS) were carried out to analyse the wear scar surface. The effect mechanism of ultrasonic vibration on friction pairs was discussed. The results indicated that ultrasonic vibration could decrease the friction and wear of GCr15/45# friction pairs, when the content of n-Al2O3 was 0.5wt%, the effect of ultrasonic vibration on friction pairs was most obvious. The friction coefficient, wear volume and wear scar depth under ultrasonic vibration decreased 10%, 34% and 13%, respectively. The friction reduction and anti-wear mechanism of n-Al2O3 was single “micro ball bearing” without ultrasonic vibration, and it changed to “micro ball bearing” and adsorption penetration film with ultrasonic vibration, so the friction coefficient and wear volume was reduced.


Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4547
Author(s):  
Bin Yang ◽  
Aiqin Wang ◽  
Kunding Liu ◽  
Chenlu Liu ◽  
Jingpei Xie ◽  
...  

SiCp/Al-Si composites with different CeO2 contents were prepared by a powder metallurgy method. The effect of CeO2 content on mechanical properties, friction and wear properties of the composites was studied. The results show that with the increase in CeO2 content from 0 to 1.8 wt%, the density, hardness, friction coefficient of the composites first increases and then decreases, the coefficient of thermal expansion (CTE) and wear rate of the composites first decreases and then increases. When the content of CeO2 was 0.6 wt%, the density and hardness of the composite reached the maximum value of 98.54% and 113.7 HBW, respectively, the CTE of the composite reached the minimum value of 11.1 × 10−6 K−1, the friction coefficient and wear rate of the composite reached the maximum value of 0.32 and the minimum value of 1.02 mg/m, respectively. CeO2 has little effect on the wear mechanism of composites, and the wear mechanism of composites with different CeO2 content is mainly abrasive wear under the load of 550 N. Compared with the content of CeO2, load has a great influence on the wear properties of the composites. The wear mechanism of the composites is mainly oxidation wear and abrasive wear under low load. With the increase in load, the wear degree of abrasive particles is aggravated, and adhesive wear occurs under higher load.


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