scholarly journals Tribological Behavior of Copper–Graphite Composites Reinforced with Cu-Coated or Uncoated SiO2 Particles

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2414 ◽  
Author(s):  
Haohao Zou ◽  
Xu Ran ◽  
Weiwei Zhu ◽  
Yong Wang ◽  
Siqi Zhan ◽  
...  

Copper–graphite composites reinforced with SiO2 particles were fabricated by powder metallurgy technique. Electroless copper plating was introduced to improve the interfacial bonding between SiO2 particles and copper matrix. The microstructure, density, and hardness of the composites were characterized. The tribological properties, such as friction coefficient and wear rate of the composites, were studied using a pin-on-ring tribometer. The results show that the hard SiO2 can restrict the severe plastic deformation and adhesion contact in the process of wear. At the same time, parts of SiO2 particles can be broken into fine particles during wear process, which is helpful for decreasing adhesion wear and abrasive wear. Therefore, the addition of SiO2 leads to increasing friction stability and friction coefficient, and decreasing wear rate. In addition, the electroless copper plating improves the interfacial bonding between SiO2 and copper matrix, which prevents separation of SiO2 from copper matrix and further increase tribological properties of the composites.

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1854
Author(s):  
Fei-xia Zhang ◽  
Yan-qiu Chu ◽  
Chang-sheng Li

This paper presents a facile and effective method for preparing Ni/NbSe2 composites in order to improve the wettability of NbSe2 and copper matrix, which is helpful in enhancing the friction-reducing and anti-wear properties of copper-based composites. The powder metallurgy (P/M) technique was used to fabricate copper-based composites with different weight fractions of Ni/NbSe2, and tribological properties of composites were evaluated by using a ball-on-disk friction-and-wear tester. Results indicated that tribological properties of copper-based composites were improved by the addition of Ni/NbSe2. In particular, copper-based composites containing 15 wt.% Ni/NbSe2 showed the lowest friction coefficient (0.16) and wear rate (4.1 × 10−5 mm3·N−1·m−1) among all composites.


Author(s):  
Jiaming Pan ◽  
Jinwei Yin ◽  
Yongfeng Xia ◽  
Dongxu Yao ◽  
Hanqin Liang ◽  
...  

In order to improve the wear resistance, Fe–Cr–C alloy and β-Si3N4 whiskers were chosen as the hard phases in bronze-graphite to prepare self-lubricating composite. Friction behaviors were tested with counter material 45# steel to evaluate the tribological properties of composites. The results indicated that Fe–Cr–C alloy and β-Si3N4 whiskers played different roles in composites. β-Si3N4 whiskers can obviously decrease the wear rate by excellent wear resistance. While the Fe–Cr–C alloy had better wettability with matrix, which improved the interfacial bonding and provided a continuous wear resistance. Moreover, Fe–Cr–C alloy also played a role in maintaining the friction coefficient stability, and this effect was more significant in the conditions of high rotational speeds. The composite containing 12.5 vol.% β-Si3N4 whiskers and 2.5 vol.% Fe–Cr–C alloy in this research showed good friction performance.


Author(s):  
Balakrishnan Anandkumar ◽  
Rani P. George ◽  
Alagarsamy Karthik ◽  
Dasnamoorthy Ramachandran ◽  
Uthandi Kamachi Mudali

Author(s):  
Ying Yan ◽  
Xuelin Lei ◽  
Yun He

The effect of nanoscale surface texture on the frictional and wear performances of nanocrystalline diamond films under water-lubricating conditions were comparatively investigated using a reciprocating ball-on-flat tribometer. Although the untreated nanocrystalline diamond film shows a stable frictional state with an average friction coefficient of 0.26, the subsequent textured films show a beneficial effect on rapidly reducing the friction coefficient, which decreased to a stable value of 0.1. Furthermore, compared with the nanocrystalline diamond coating, the textured films showed a large decreasing rate of the corresponding ball wear rate from 4.16 × 10−3 to 1.15 × 10−3 mm3/N/m. This is due to the fact that the hydrodynamic fluid film composed of water and debris can provide a good lubrication environment, so the entire friction process has reached the state of fluid lubrication. Meanwhile, the surface texture can greatly improve the hydrophilicity of the diamond films, and as the texture density increases, the water contact angle decreases from 94.75° of the nanocrystalline diamond film to 78.5° of the textured films. The proper textured diamond film (NCD90) exhibits superior tribological properties among all tested diamond films, such as short run-in period, low coefficient of friction, and wear rate.


Vacuum ◽  
2021 ◽  
pp. 110330
Author(s):  
Chunming Wang ◽  
Luming Zeng ◽  
Wucheng Ding ◽  
Tongxiang Liang

2010 ◽  
Vol 654-656 ◽  
pp. 2763-2766 ◽  
Author(s):  
Li Wen Mu ◽  
Xin Feng ◽  
Yi Jun Shi ◽  
Huai Yuan Wang ◽  
Xiao Hua Lu

The tribological properties of polyimide (PI) composites reinforced with graphite or MoS2 sliding in liquid alkali and water as well as dry friction were investigated using a ring-on-ring tester. The results show that the friction coefficient (μ) and wear rate (W) for both graphite/PI and MoS2/PI composites in different liquid mediums are μdry>μwater >μalkali and Wwater>Wdry >Walkali. Results also indicate that the friction coefficient and wear rate of the PI composites filled with different solid lubricants are μMoS2 >μgraphite and W MoS2 >Wgraphite in different liquid mediums. In addition, the hydrophobic inorganic fillers are fit for the reinforcement of polymer-based composites sliding in liquid mediums. It is also concluded from the authors’ work that the wear rate and friction coefficient of polymer-based (such as PI, PTFE) composites in the alkali lubricated conditions is lowest among all the friction conditions. This may be attributed to the ionic hydration in the alkaline solution.


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