Electromechanical Behavior of the Copper-Based Graphene- and Al2O3- Reinforced Hybrid Composite Electric Motor Brushes

Abstract

This study investigates the fabrication and characterization of electric motor brushes, which serve as critical conductive and wear-resistant components in direct contact with the motor’s rotor. Copper-matrix composites reinforced with varying concentrations of graphene and alumina (Al2O3) were produced across two distinct experimental groups. Following an 8-hour mechanical alloying process, the composite powders were consolidated using a single-acting hydraulic press. The resulting compacts were then sintered at 900°C (1 hour) in a reducing environment. Electromechanical evaluations were conducted in triplicate at a constant spring pressure (100 kPa), varying rotational speeds (8–32 m/s), and current densities (4–16 A/cm2). The study further assessed the electrical conductivity, porosity, hardness, and mass loss of each specimen. Results indicate that electrical conductivity declined as the reinforcement ratio increased. Regarding tribological performance, the minimum friction force (0.08 N) was recorded for the 5 wt. % graphene and 1 wt. % Al2O3 composition. Meanwhile, the lowest voltage drop (0.03 V) was observed in the 10 wt. % Gr and 0.5 wt. % Al2O3 sample. Although hardness generally decreased with higher reinforcement content. On the other hand, the copper-based composite containing 10 wt. % Gr and 0.5 wt. % Al2O3 exhibited the maximum hardness value of 13.8 HB.

Keywords

• Mechanical milling
• Metal matrix composites
• Electric motor brushes
• Copper-based brushes
• Graphene

Supporting Institution

Karadeniz Technical University

Project Number

FHD-2016-5709

Ethical Statement

Authors approve that to the best of their knowledge, there is not any conflict of interest or common interest with an institution/organization or a person that may affect the review process of the paper.

Thanks

This study supported by Scientific Research Projects Unit of Karadeniz Technical University with the project no. FHD-2016-5709

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