KH-570 Silane modification for enhanced graphene/silver nanocomposite brush plating: Process optimization and Tribo-corrosion properties

The agglomeration of graphene in conventional silver composite plating baths significantly compromises coating homogeneity and performance. This study introduces γ-methacryloxypropyl trimethoxysilane (KH-570) as a silane coupling agent to functionalize graphene, enhancing its dispersion and interfacial adhesion with the silver matrix. Pure silve, unmodified graphene/silver (G/Ag), and KH-570-modified graphene/silver (MG/Ag) coatings were fabricated via brush plating under varying voltages (3 V, 4 V, 5 V). Systematic investigations revealed that the MG/Ag coating exhibited superior microstructural compactness, with 64% higher microhardness (HV 140) and 65% lower wear rate compared to pure Ag. Electrochemical tests in 3.5% NaCl demonstrated a one-order-of-magnitude reduction in corrosion current density (0.086 × 10 −6  A/cm 2 ) for the 4 V MG/Ag coating, alongside a hydrophobic surface (contact angle: 112°) and reduced contact resistance (0.58 μΩ). The optimized voltage of 4 V facilitated refined grain structures, minimized defects, and enhanced graphene dispersion through covalent Si O C bonding. These improvements stem from KH-570's dual role in preventing graphene agglomeration and strengthening the Ag-graphene interface. The MG/Ag coating demonstrates exceptional wear resistance, corrosion inhibition, and electrical stability, positioning it as a robust candidate for high-voltage disconnectors in harsh outdoor environments. The concentration of KH-570 used in this study is analytical reagent (AR). This work provides a scalable, eco-friendly strategy for advancing durable electrical contact materials.