The structure of tribolayers at the commutator and brush interface: A case study of failed and non-failed DC motors

Fakih, B.; Dienwiebel, Martin

doi:10.1016/j.triboint.2015.05.008

Cited by 14 publications

(7 citation statements)

References 10 publications

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“…The copper rings are usually rotors and the caron brushers are usually the stators. The electrical erosion due to local electric arc generated is also observed along with the mechanical wear at the ring and brush contacts [82]. There are a lot of parameters that are reported in the past, about the tribological failure of the carbon brushes.…”

Section: Tribology In Electric Motormentioning

confidence: 99%

“…There are a lot of parameters that are reported in the past, about the tribological failure of the carbon brushes. They are current density, the humidity of operation, brush spring pressure, water vapor in the commutator film, brush resistivity, commutator temperature, and current commutation [82][83][84][85]. The generic parameters that affect the efficiency of the copper ring and carbon brush assembly are material systems, geometry, contact surface morphology, and overall operating conditions.…”

Section: Tribology In Electric Motormentioning

confidence: 99%

See 1 more Smart Citation

Hybrid and electric vehicle tribology: a review

Hemanth¹,

Ananthapadmanabha²

2021

Surf. Topogr.: Metrol. Prop.

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This comprehensive review article provides a cumulative insight into the tribology and the surface topography of the components of the electric vehicles (EV) and hybrid electric vehicles (HEV) that are subjected to friction and wear under their conventional operation. The comparison between the components that are native to EV and HEV and components that are common for both vehicle types are discretely discussed. The overall influence of such a tribology-critical component on the life and efficiency of the EV and HEV is indicated in this article as well. Identification of the research gaps in the key areas paves an avenue to channel the research and focus upon improving the efficiency of EV and HEV by improvising the design, materials, power harness, and lubrication techniques. Finally, the future scope of the global EV and HEV markets are discussed to signify the importance of the studies on the tribology of the trending automobile field. RECEIVED

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Section: Tribology In Electric Motormentioning

confidence: 99%

Section: Tribology In Electric Motormentioning

confidence: 99%

Hybrid and electric vehicle tribology: a review

Hemanth¹,

Ananthapadmanabha²

2021

Surf. Topogr.: Metrol. Prop.

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“…Most studies on friction and wear properties of C/Cu composites and reinforcement materials in different conditions are carried out from a macro perspective, , such as observing the friction coefficient, the wear rate, and scanning electron microscopy (SEM) diagrams . However, few studies have observed the morphology, structure, and crystal changes before and after friction experiments from a microscopic perspective.…”

Section: Introductionmentioning

confidence: 99%

Intuitive Analysis of the Microtribological Behavior of Copper-Coated Graphite–Graphite/Cu Composites with High Graphite Contents

Zhu

et al. 2022

ACS Omega

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To improve the combination of graphite and copper, the friction and wear of a graphite/copper composite with a high content of graphite (50 wt %), copper-coated graphite were used to modify it. To observe the distribution law of each phase in the material and the change of composite surface structure after the friction and wear experiment, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the micro-structure, friction film, debris, and friction cross section of the composites. The results show that the large particle size of copper-coated graphite is anisotropic in the material, which helps to form a friction film with a high graphite content on the contact surface. TEM images of the friction film and debris directly reflect the structure changes of graphite and copper during friction; under normal load and shear force, interlamellar detachment and interlamellar fracture of graphite occur, and its edge is folded and crimped, resulting in the loss of an ordered state in some regions, which results in the instability of crystal lattice and the transition from an ordered to disordered state of graphite, resulting in the (002) halo ring in FFT results. Severe plastic deformation and oxidation reactions occur in copper, and copper oxides are formed, forming a high-strength and smooth oxide film in the metal-rich area and improving the wear resistance of the material. TEM images of the friction section directly show that an inverted triangular deformation zone is formed on the surface of the sample after friction and wear experiments. The edge of the deformation zone is stepped, consisting of a drag zone and an accumulation zone, and the surface of the contact zone is covered by a carbon film.

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“…Because of the poor wettability between graphite phase and copper phase [9] ,each phase of the composites can only be connected by mechanical bounding and physical bonding,resulting in the poor binding effect between the two phases and there are voids existing in the composites [10] ,which seriously affects the mechanical properties and wear-resisting property of the composites.To improve the bonding strength and enhance the properties of the composites,some measures such as the addition of alloying elements which are prone to form carbides [11] ,the addition of new carbon material reinforcing agents and the modi cation of the graphite surface have been taken [12] .Many scholars have improved the mechanical properties and friction properties of composites by adding appropriate new high-performance materials such as carbon nanotubes(CNTs) [13] ,carbon bers(CF) [1] and graphene [14,15] .However,the nanomaterials are prone to agglomeration due to the high surface activity [16] ,which limits the amount and application elds of nano-materials.Metal coating on the surface of carbon material is a feasible method to improve the bonding strength [17] .Numerous studies show that the copper,nickel [18] and silver coating on the surface of carbon materials can availably improve the bonding strength between the strengthened graphite and metal phases.After a lot of research and exploration,the technology of preparing metalcoated graphite has become mature,the preparation cost of the composites have also been reduced,which can be effectively applied in industrial preparation.Wear resistance is an important property that affects the use of G/Cu composite materials [19] .A large number of scholars have studied the friction and wear performance of C/Cu composites and the reinforcement materials in different conditions from macro perspective [20,21] ,the friction mechanisms are derived by observing the friction coe cient,wear rate and SEM diagrams [22] .But few studies have observed the morphology,structure and crystal changes before and after the friction experiment from the micro perspective.…”

Section: Introductionmentioning

confidence: 99%

The Micro-Tribological Behavior and Friction Mechanism of the Graphite/Cu Composites and Copper-coated Graphite-graphite/Cu Composites

Zhu

Zhang

et al. 2021

Preprint

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The ring-block tribological behavior of the graphite/Cu(G/Cu) composites and copper-coated graphite-graphite/Cu(CCG-G/Cu) were studied by observing the friction coefficient,wear rate,microstructure and morphogoly of the composites after friction experiments.SEM and TEM were used to character the micro-morphology and micro-structure of debris,friction surface and friction cross section of the composites.The results show that adding 20wt% copper-coated graphite could reduced the friction coefficient and wear rate of the composites.The micro-morphology and micro-structure show that the copper phase are undergo oxidation and plastic deformation under cyclic stress,results in abundant deformation area in copper-rich zones.Interlaminar shedding and intramolecular tearing occurs in graphite phase,and then laid flat on the friction surface,forming a friction film with higher integrity and reducing the friction coefficient of the composites.The TEM images of the friction cross section show that deformation zone is mainly composed of accumulation zone,drag zone and carbon film.The simulation of the friction process shows that the initial stage is mainly dominated by abrasive wear and adhesive wear.With the progress of the experiment,the exposed copper phase is oxidized and oxidative wear occurs,graphite is shed and transferred to the contact surface.In the later stage of the experiment,a complete friction film with high graphite content is formed on the contact surface,which is mainly dominated by fatigue wear.

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The structure of tribolayers at the commutator and brush interface: A case study of failed and non-failed DC motors

Cited by 14 publications

References 10 publications

Hybrid and electric vehicle tribology: a review

Hybrid and electric vehicle tribology: a review

Intuitive Analysis of the Microtribological Behavior of Copper-Coated Graphite–Graphite/Cu Composites with High Graphite Contents

The Micro-Tribological Behavior and Friction Mechanism of the Graphite/Cu Composites and Copper-coated Graphite-graphite/Cu Composites

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