Electrodeposited Ni-W coatings as the effective reaction barrier at Ga-21.5In-10Sn/Cu interfaces

Abstract

In this study, the long-term (up to 400 days) room temperature aging tests for Ga-21.5In-10Sn/Cu interface were investigated, confirming the formation of intermetallic compounds at room temperature could cause the serious interfacial instability issues. One novel strategy using solid solution alloys with high thermal stability and high diffusion activation energy to design the barrier layer materials to inhibit the diffusion of solid atoms or interfacial reactions was proposed. The feasibility of Ni-W and Ni-W-graphene coatings as the interfacial reaction barrier of Ga-21.5In-10Sn/Cu liquid-solid interfaces was explored, indicating a novel application of Ni-W electroplated coatings in electronic/electrical contacts fields besides these traditional applications in wear-resistance, corrosion-resistance and heat corrosion resistance fields. The challenging agglomeration issues of graphene in water soluble solutions was successfully solved using the ethylene glycol as the effective dispersant. The temperature dependence of Ni-W and Ni-W-graphene coatings as the interfacial reaction barrier was compared. It was preliminarily contended that the addition of graphene particles was detrimental to improve the reaction barrier properties of Ni-W matrix. This finding provides a novel strategy to solve the interfacial instability problem of Ga-21.5In-10Sn/Cu interfaces and will enable wider applications of electroplated Ni-W coatings, promoting the development of soft and stretchable Ga-based alloys/Cu conductors in wearable electronics.