Oxidation on the current-carrying rolling surface and its subsequent impact on the damage of Cu contact pairs in O2/N2 mixture

Sun, Yixiang; Song, Chenfei; Zhang, Yanyan; Li, Mengjia; Zhang, Yongzhen

doi:10.1016/j.matlet.2021.129349

Cited by 11 publications

(4 citation statements)

References 13 publications

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“…It can be seen that the COF has a slight rising trend at 10% RH with the increase of cyclic time, on the contrary, decrease at the remaining humidity conditions. This is because the worn surface is prone to produce oxide in a dry environment, which should be the oxidation-induced effects leading to an increase in COF [24]. However, under high humidity conditions, water vapor participates in the friction process, and the water medium is increasingly adsorbed on the surface, providing the lubrication effect which is beneficial to reducing friction [25].…”

Section: Effort Of Humidity On Friction Coefficientmentioning

confidence: 99%

The role of relatively humidity in friction and wear behaviors of carbon sliding against copper with electric current

Ji¹,

Li²,

Shen³

et al. 2021

Surf. Topogr.: Metrol. Prop.

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During the train operation, the pantograph/catenary system is subjected to an extremely harsh service environment. Relative humidity has a great influence on the current-carrying tribological behaviors of carbon strips. The identification and understanding of the wear mechanism are extremely important in wet and dry conditions. This study was carried out to investigate the humidity effect on the service properties of carbon sample rubbing against copper (Cu) with and without electric current using a home-made wear tester, and the humidity ranging from 10% RH to 80% RH. The results indicate that the sliding wear behavior of the friction interface is drastically affected by the intervention of water vapor and electric current. The coefficient of friction (COF) without current is obviously lower than current-carrying sliding when the humidity is constant. However, the increased humidity led to a decreasing trend. After the current increases to 10 A, all the COF values are closed to each other ultimately. These phenomena mainly result from the formation and destruction of water lubrication film. Furthermore, the tribo-pairs worn surface appears the most sensitive to the current effect under dry conditions. The reverse transfer of Cu and carbon is greater on account of the current agglomeration effect, and the oxidation degree is more severe. The wear mechanisms of carbon are mainly material transfer accompanying with oxidation erosion. However, the wear degradation is weakened under water lubrication and uniform current distribution which improves the conductive quality. This is the coupling effect of humidity environment, current and heat concentration. This experiment provides technical support for the operation of an electric locomotive under an extremely harsh service environment.

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Section: Effort Of Humidity On Friction Coefficientmentioning

confidence: 99%

The role of relatively humidity in friction and wear behaviors of carbon sliding against copper with electric current

Ji¹,

Li²,

Shen³

et al. 2021

Surf. Topogr.: Metrol. Prop.

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show abstract

“…Meanwhile, chemical oxidation and electrochemical oxidation occur, and the characteristics of abrasive wear and adhesive wear are signi cant, leading to increased wear loss of carbon. A decrease in COF and an increase in contact resistance result from the thickening of the copper oxide lm, which has a greater adsorption capacity for water molecules than pure copper [32] . The variation of the COF with the current is consistent with the results of literature [33].…”

Section: Resultsmentioning

confidence: 99%

The effect of temperature on the current-carrying tribological behevior of C/Cu contact pairs in high humidity environments

Ji,

Xiao,

et al. 2024

Preprint

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The environmental temperature alters the frictional behaviour by changing the state of the current-carrying contact interface, which makes the electrical contact invalid. In this work, the effects of three different temperatures (-20 ℃, 0, 20 ℃) on the current-carrying tribological behaviour of C-Cu tribo-pairs in high humidity environment (85%) were discussed. The evolution laws of friction coefficient, wear volume, contact surface properties, and contact resistance of C-Cu contact pairs under the coupling effect of temperature and current were studied, and the current- carrying wear mechanism of C-Cu at low temperature was analyzed in depth. The friction coefficient at each temperature exhibits a similar changing rule before and after current-carrying, demonstrating that the friction coefficient increases as temperature falls. However, the average friction coefficient at each temperature is lower than that without current. Although it will hasten the material surface's oxidation, a drop in ambient temperature will effectively lessen the transfer behavior of copper to carbon surface and reduce the wear volume of carbon material. The amount of copper transferred increases as current rises. Compared with the current, the change of temperature has a greater impact on the damage of tribo-pairs. At room temperature, the contact resistance under high current is greater than that of low current, the low temperature is just the opposite. In addition, at 0℃, although the contact resistance of low current (5 A) decreases significantly in the early stage of friction, its average resistance and fluctuation amplitude are the largest. As the temperature decreases, the current-carrying wear mechanism of C-Cu contact pairs gradually changes from adhesive wear to fatigue wear.

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“…GB wetting by the second solid phase can have a strong influence on the properties of materials, including Al alloys [18,20,22,23,[25][26][27][28][29][30][31][32][33][34][35], Fe-based alloys and steels [36,, Co-and Ni-based alloys [78][79][80][81][82][83][84][85], Cu alloys [86,88,90], Ti-and Zr-based alloys [91,93,95,97,, Mg alloys [124,126,[128][129][130][131], as well multicomponent and high-entropy alloys [132,134,[136][137][138][139][140][141][142][143][144].…”

Section: Influence Of Gb Wetting By the Second Solid Phase On The Pro...mentioning

confidence: 99%

“…Almost 20 years have passed since the discovery of the phenomenon of GB wetting by other solid phases in 2004 [17]. The indications of GB wetting by other solid phases were found and studied in a large circle of systems such as Al alloys [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35], Fe-based alloys and steels , Co-and Ni-based alloys [77][78][79][80][81][82][83][84][85], Cu alloys [86][87][88][89][90], Ti-and Zr-based alloys , Mg alloys [124][125][126][127][128][129][130][131], as well multicomponent and high-entropy alloys [132][133][134][135][136]…”

Section: Introductionmentioning

confidence: 99%

Grain Boundary Wetting by the Second Solid Phase: 20 Years of History

Straumal

Lepkova

Korneva

et al. 2023

Metals

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Grain boundaries (GBs) can be wetted by a second phase. This phase can be not only liquid (or melted), but it can also be solid. GB wetting can be incomplete (partial) or complete. In the case of incomplete (partial) wetting, the liquid forms in the GB droplets, and the second solid phase forms a chain of (usually lenticular) precipitates. Droplets or precipitates have a non-zero contact angle with the GB. In the case of complete GB wetting, the second phase (liquid or solid) forms in the GB continuous layers between matrix grains. These GB layers completely separate the matrix crystallites from each other. GB wetting by a second solid phase has some important differences from GB wetting by the melt phase. In the latter case, the contact angle always decreases with increasing temperature. If the wetting phase is solid, the contact angle can also increase with increasing temperature. Moreover, the transition from partial to complete wetting can be followed by the opposite transition from complete to partial GB wetting. The GB triple junctions are completely wetted in the broader temperature interval than GBs. Since Phase 2 is also solid, it contains GBs as well. This means that not only can Phase 2 wet the GBs in Phase 1, but the opposite can also occur when Phase 1 can wet the GBs in Phase 2. GB wetting by the second solid phase was observed in the Al-, Mg-, Co-, Ni-, Fe-, Cu-, Zr-, and Ti-based alloys as well as in multicomponent alloys, including high-entropy ones. It can seriously influence various properties of materials.

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Oxidation on the current-carrying rolling surface and its subsequent impact on the damage of Cu contact pairs in O2/N2 mixture

Cited by 11 publications

References 13 publications

The role of relatively humidity in friction and wear behaviors of carbon sliding against copper with electric current

The role of relatively humidity in friction and wear behaviors of carbon sliding against copper with electric current

The effect of temperature on the current-carrying tribological behevior of C/Cu contact pairs in high humidity environments

Grain Boundary Wetting by the Second Solid Phase: 20 Years of History

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