▎ 摘　　要

This study investigated the interfacial reaction, the microstructure, and the hardness of the SAC305-xNi solder on both Cu and graphene-coated Cu (G-Cu) substrates. The experimental results indicate that the increase of Ni content in the solder leads to the roughness of the (Cu, Ni)(6)Sn-5 IMC layer on Cu. In contrast, the growth of the (Cu, Ni)(6)Sn-5 interfacial IMC, which results from increasing Ni addition, is significantly suppressed on G-Cu substrates. As the concentration of Ni ranges from 0 to 0.2 wt%, the microstructure of the solder bulks on Cu substrates shows slight changes. The hardness of the solder bulks in SAC305-Ni/Cu is similar to that in the SAC305/Cu solder joint. The amount of beta-Sn rises and the eutectic area shrinks due to increasing Ni addition in the solder bulks on G-Cu substrates. Therefore, the solder bulks in the SAC305-Ni/G-Cu show lower hardness than that in the SAC305/G-Cu solder joint.