Tribological behavior and morphology of PTFE particulate-reinforced POM matrix composites

2017 ◽  
Vol 37 (3) ◽  
pp. 227-237 ◽  
Author(s):  
Qi Liu ◽  
Wei Luo ◽  
Shengtai Zhou ◽  
Huawei Zou ◽  
Mei Liang

Abstract The friction and wear properties of polyoxymethylene/polytetrafluoroethylene (POM/PTFE) composites were investigated by using a block-on-ring friction tester and special focus was paid to the effect of weight average molar mass (Mw) of POM. To study the thermodynamic characteristics and wear mechanism of composites, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were used. Results showed that friction and wear properties of the composite blends were strongly affected by the Mw of POM and the loading fractions of PTFE. POM/PTFE composites with lower Mw of POM owned better wear resistance abilities under a high-speed sliding regime, which resulted from the effective lubrication of transferred wear debris under a relatively high sliding speed. However, the transfer layer on the counterface could be easily peeled off under the low sliding speed, resulting in higher wear rate of POM/PTFE composites with lower Mw of POM. POM and its composites with high Mw showed comparative high friction levels, related to the strong adhesion between the resin and the steel counterpart. DSC analysis showed that POM with lower Mw had higher crystallinity, which was beneficial to the improvement of wear resistance in a high-speed sliding condition.

2018 ◽  
Vol 70 (9) ◽  
pp. 1706-1713 ◽  
Author(s):  
Guotao Zhang ◽  
Yanguo Yin ◽  
Ting Xie ◽  
Dan Li ◽  
Ming Xu ◽  
...  

Purpose This paper aims to obtain high mechanical and good tribological properties of epoxy resin-based coatings under dry friction conditions. Design/methodology/approach Bonded solid lubricant coatings containing Kevlar fibres were prepared by a spraying method. The friction and wear properties of the coatings were experimentally investigated with a face-to-face tribometre under dry friction conditions. Scanning electron microscopy, energy dispersive X-ray spectroscopy and 3D laser scanning technologies were used to characterise the tribological properties. The action mechanism of the Kevlar fibres on a solid lubricant transfer film was also analysed. Findings Adding Kevlar fibres can significantly improve the wear resistance of the coatings. When the Kevlar fibre content increases, the tribological properties of the coatings improve and then worsen. Superior properties are obtained with 0.03 g of Kevlar fibres. Appropriately increasing the load or speed is beneficial to the removal of the outer epoxy resin and the formation of a lubricant film. During friction, the solid lubricants wrapped in the epoxy resin accumulate on the surface to form a transfer film that shows a good self-lubricating performance. In the later friction stage, fatigue cracks occur on the solid lubricant film but cannot connect to one another because of the high wear resistance and the entanglement of the rod-like Kevlar fibres. Thus, no large-area film falls from the matrix, thereby ensuring the long-term functioning of solid lubricant coatings. Originality/value Epoxy resin-based solid lubricant coatings modified by Kevlar fibres were prepared, and their friction and wear properties were investigated. Their tribological mechanisms were also proposed. This work provided a basis for the analysis of the tribological properties and design of bonded solid lubricant coatings containing Kevlar fibres.


Lubricants ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 11 ◽  
Author(s):  
Jankhan Patel ◽  
Amirkianoosh Kiani

In this study, reduced graphene oxide (rGO) nano platelets were used as an additive to enhance friction and wear properties of oil-based lubricants by preparing three samples at 0.01% w/w, 0.05% w/w, and 0.1% w/w concentrations. To analyze the direct effect of rGO nano platelets on tribological properties, 99.9% pure oil was used as a liquid lubricant. A comparative tribological study was done by performing a ball-on-disk wear test in situ under harsh conditions, which was further analyzed using a non-contact 3D optical profilometer. Morphological evaluation of the scar was done using transmission and scanning electron microscopy (TEM, SEM) at micro and nano levels. The lubricants’ physical properties, such as viscosity and oxidation number, were evaluated and compared for all samples including pure oil (control sample) as per ASTM standards. Findings of all these tests show that adding rGO nano platelets at 0.05% w/w showed significant reduction in friction at high speed and in wear up to 51.85%, which is very promising for increasing the life span of moving surfaces in machinery. Oxidation and viscosity tests also proved that adding rGO nano platelets to all samples does not sacrifice the physical properties of the lubricant, while it improves friction and wear properties.


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.


2013 ◽  
Vol 764 ◽  
pp. 55-59
Author(s):  
Zhan Bin Guo ◽  
Song Lin Gao

The friction and wear properties of several common metal materials (45#, 25CrMn, and 40CrNiMo) friction pair under oil lubrication was investigated on M-200 Type wear tester, and studied the friction under the condition of differ sliding speed and pressure. The results show that: the 25CrMn/45# steel pair has better tribological and wear performance; the load is the main factor which influences the friction of the material at the low sliding speed; the main wear form is adhesive wear, but the wear mechanism is gradually became from adhesive wear to abrasive wear and flaking wear with the contact pressure and sliding speed increased.


2014 ◽  
Vol 8 (1) ◽  
pp. 125-128 ◽  
Author(s):  
Tao Ding ◽  
Wenjing Xuan ◽  
Qiudong He ◽  
Hao Wu ◽  
Wei Xiong

A series of experiments on friction and wear properties of carbon strip rubbing against copper contact wire is performed on high-speed friction and wear tester with electric current. The results show that the friction coefficient is generally maintained between 0.24 and 0.37. In the absence of electric current, the coefficient of friction is higher than that in the presence of electric current. The wear rate of carbon strip materials is generally not more than 0.014g/km. In particular, the wear rate under the electric current of 240 A is 14 times more than that in the absence of electric current. By observing the scar of worn surface with optical microscope, it can be found that there are obvious slip scars and arc erosive pits. The dominated wear mechanisms are abrasive wear and arc erosion in electrical sliding frictional process.


2020 ◽  
Vol 12 (6) ◽  
pp. 806-809
Author(s):  
Ghanshyam Dass ◽  
Anil Kumar ◽  
Manoj Kumar Kushwaha

Friction and wear properties of NAAO templates were calculated in affinity to pore dimensions and applied load. Homogeneously uniformly decorative synthesized by anodization of nanoporous aluminium oxide films having 65–95 μm thick and pores of 143.5, 105, 84.4 nm diameter. A tribological competency of the material checked out with loads and 250 rpm on the pin on a dry wear disc. The anodized NAAO sample has wear resistance increased by 25% as compared to the non-anodized sample. The pore density little bit impressed the frictional characters of NAAO template. We counsel that these course templates basically contribute to the reduction of friction distrait the pore structure by proving energy-dispersive spectroscopy (EDS).


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