Preparation and properties of copper-plated expanded graphite/ copper composites

The porous expanded graphite (EG) was metallized by electroless plating to improve the C-Cu interface bonding, and the copper-plated EG/Cu (EG@Cu/Cu) composites with different EG content (1-4 wt%) were fabricated by spark plasma sintering (SPS). The effects of EG content on the microstructure, physical properties, bending properties, and tribological properties of EG@Cu/Cu composites were studied in detail. The results show that the copper-plated composite powder inherits the worm structure of EG, and forms a dense copper coating with a thickness of 2-5 mu m. During electroless plating, the plating solution penetrated into the EG particles and formed a microscopic 3D Cu network. Compared with the composite without copper plating, copper coating effectively improves the interface bonding of C-Cu. EG@Cu/Cu composites retain the physical and mechanical properties of Cu matrix, and obtains lower friction coefficient and wear rate. The discrete and uniform distribution of EG improves the continuity of Cu matrix. When subjected to friction, the flexible EG could overflow from the surface within 10 min to form a saturated self-lubricating film. EG@Cu/Cu composite with 3 wt% EG has better comprehensive properties, the friction coefficient is 22.9% of pure copper, and the wear mass is 7.9% of pure copper. Abrasive wear is the main friction mechanism of EG@Cu/Cu composites.

Automated summary

The study focused on the microstructure, physical properties, and tribological properties of EG@Cu/Cu composites with different EG content. The results showed that the copper coating effectively improved the interface bonding between C-Cu, and the uniform distribution of EG improved the continuity of the copper matrix, forming a self-lubricating film during friction.