Investigating the synergistic effect of CNT + MLG hybrid structure on copper matrix and electrical contact properties of the composite

Abstract

In this study, carbon nanotubes (CNTs) and multi-layer graphene (MLG) were mixed and reinforced into copper matrix at the rates of 1, 2 and 10 vol.%. Thus, the synergistic effect of CNT $$+$$ MLG hybrid structure on copper matrix was investigated and the usability of the obtained composite as an electrical contact material was examined. In addition, changes in the properties of the composite were demonstrated with the changes in amounts of CNTs and/or MLGs in Cu matrix. In this study, both reinforcements and composites were produced under laboratory conditions. The electrical conductivity, abrasion properties, and hardness of the produced composites and their usage as electrical contact material were investigated. The obtained results were compared with previous studies, and their reasons were revealed. The electrical conductivity of the obtained composite increased first to a certain reinforcement amount with the increasing CNT $$+$$ MLG hybrid reinforcement rate and then decreased. However, the electrical conductivity of the composite reinforced with only CNTs or MLGs at the same rate was found to be higher than CNTs $$+$$ MLGs reinforced composite. The abrasion resistance of CNT $$+$$ MLG hybrid-reinforced copper matrix composite showed an increase with increasing reinforcement ratio. The increase in the amount of MLGs in the composite caused an increase in the abrasion resistance of the composite. This situation can be said to be caused by the lubricant property of MLGs. CNT $$+$$ MLG hybrid-reinforced copper matrix composites were used as an electrical contact material in an experimental set-up, and this material loss in these materials and the damages on the surfaces after 20,000 turn on/off were investigated. It can be asserted that the electrical contact properties of the composite improved with increasing amount of MLGs. MLGs distributed rapidly the heat generating during the operation of the contact and weakened the mechanical effects during the on/off states of the contacts due to their lubricant properties which helped to reduce the damage on the contact materials.