The study of microstructure characterization: Cu modified Cu-Ni-graphite composite

ABSTRACT

Cu-coated graphite was applied to modify the interface of Cu-Ni-graphite composite used as switch slide baseplate. Up to now, interfacial characterization and modification mechanisms of Cu modified Cu-Ni-graphite composite are seldom researched. In this study, Cu-coated graphite was deposited by chemical plating, and Cu modified Cu-Ni-graphite composite was prepared by powder metallurgy. Both the microstructure characterizations of Cu-coated graphite and interfacial morphologies of the composite were investigated. Then, the comparison of mechanical properties of unmodified and Cu modified Cu-Ni-graphite composite was discussed. The results showed that the Cu coating was made of fine particles with uniform distribution and with the average thickness of 1.05 μm. The mutual diffusion was about 2.54 μm width at the interface. The interfacial modification mechanism of Cu coating in the composite was that the decreasing of diffusion activity both in the graphite and matrix; and the increase of diffusion driving force at the interface. The interfacial bonding method in the transition from mechanical bonding to the combination of mechanical bonding and diffusion bonding. Compared with the unmodified composite, the flexural strength raised 24.4%, and hardness increased by 9%.

GRAPHICAL ABSTRACT

KEYWORDS:

• Surface treatment
• coating
• Cu-Ni-graphite composite
• interfacial modification

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [51805408]; the Guangxi Innovation-Driven Development Project [GUIKEAA18242001];the Science and Technology Project of Guangdong Province in China [2015B010122003]; the Science and Technology Project of Guangdong Province in China [2015B090926009]; the Science and Technology Project of Guangzhou City in China [201604046009]; the Natural Science Foundation of Shaanxi Province of China [2018JM5002].