Study on structural characteristics of composite coating on copper substrate wire surface

Abstract

To advance the utilization and development of copper-based composite wires, various samples were fabricated, including composite copper wires with Ag-Gr coated, Ag/Gr coated, and drawn Ag/Gr coatings. This study compared and analyzed the morphological characteristics, microstructure, and elemental distribution across different types of composite wires and their interfaces. The findings reveal a robust bonding interface between the composite coating and the copper wire substrate. Notably, interfaces between differing materials varied significantly, categorized either as serrated or flat. A mutual diffusion zone was observed at these interfaces. The coatings contained three primary elements: Cu, Ag, and Gr. Notably, graphene exhibited a higher propensity for diffusion within the silver coating than in the copper wire substrate. In comparison to the pure silver coating, the Ag-Gr mixed coating displayed finer grains, predominantly lath-shaped, with the presence of twinning. Macroscopic examination revealed the surface of the as-plated Ag-Gr coating to be of superior quality. The as-plated Ag/Gr coating exhibited an uneven, close-packed cell structure, which significantly improved in quality after drawing.