Effects of Contact Pressure and Sliding Speed on the Unlubricated Friction and Wear Properties of Zn-15Al-3Cu-1Si Alloy

2016 ◽  
Vol 59 (6) ◽  
pp. 1114-1121 ◽  
Author(s):  
Ali P. Hekimoğlu ◽  
Temel Savaşkan
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.


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.


Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 293 ◽  
Author(s):  
Dae-Hyun Cho ◽  
Jaehyuck Jung ◽  
Chan Kim ◽  
Jinhwan Lee ◽  
Se-Doo Oh ◽  
...  

In the present study, dry friction and wear properties of atomically thin CVD-grown graphene and MoS2 films on SiO2/Si substrates were compared at low (72 MPa) and high (378 MPa) contact pressures. Analysis of atomic force microscopy images of these films verified that the MoS2 films, which were directly grown on the SiO2/Si substrates, had clean surfaces and made conformal contacts with the substrates. In contrast, the graphene film showed many contaminants on its surface and was loosely bonded with its SiO2/Si substrate due to its wet transfer from a Cu foil to the substrate. The MoS2 film exhibited friction and wear properties superior to those of the graphene film both at low and high contact pressures. We found that the clean sliding surface and strong bonding with SiO2/Si were the main causes of the superiority of the MoS2 film compared to the graphene film. Mild wear occurred in a layer-by-layer fashion at low contact pressure for the MoS2 film. At high contact pressure, severe wear occurred due to failure at the boundary between the MoS2 films and the underlying substrates. At both contact pressures, friction did not increase immediately after the removal of the MoS2 film from the SiO2/Si substrate because the film transferred onto the counter sliding surface and served as a lubricant.


2013 ◽  
Vol 756-759 ◽  
pp. 132-137
Author(s):  
Chao Li ◽  
De Gui Zhu ◽  
Qing Yi Huang

C-Cu composites reinforced with carbon fiber cloth were prepared by hot pressing sintering technology. Wear test was conducted with copper ring under dry friction condition. The effects of load and sliding speed on friction and wear properties of the composites were studied respectively and meanwhile the wear mechanism was analyzed by combination with the morphologies of worn surfaces. The results show that carbon fiber cloth improves the wear resistance of composites and fiber grindings possess the ability of alleviating adhesive wear. These make abrasion loss small in the range of normal load and sliding velocity. With increasing of the load and sliding speed, friction coefficient and abrasion loss also increase. The main wear mechanism is transformed from slight adhesive wear into delamination wear and is accompanied by abrasive wear and slight oxidative wear at the same time.


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