Wetting behavior and interfacial reactions of Cu–20Sn–2Cr alloy on various carbon substrates

The effect of different carbon sources (CS) and the underlying mechanisms on wetting behavior, interfacial reaction products, and spreading kinetics at the reactive wetting interface between Cu-based alloys and carbon materials during brazing and composites preparation remain unclear. This study investigates the reactive wetting behavior of a Cu–20Sn–2Cr alloy on various carbon substrates (graphite (C gr ), polycrystalline diamond (C PD ), vitreous carbon (C V ), and multi-walled carbon nanotubes Bucky paper (C MW )) at 1100 °C using a modified sessile drop method. The results indicate the equilibrium contact angle ( θ e ) of C gr (7°), C PD (8°), and C V (11°) are close to each other, whereas the θ e values of C MW-back (83°) and C MW-front (69°) are higher. The reaction product layer (RPL) in C gr , C PD , and C V consists of a continuous and dense chromium carbides (Cr m C n ); the interface of C MW exhibit an “alloy + nanoscale Cr 3 C 2 cluster" transition zone. The spreading kinetics of C gr , C PD and C MW are controlled diffusion of Cr atoms to the triple line (TL) front, while Cv is controlled first by the diffusion of Cr atoms to the TL front, then is controlled by the reaction between Cr and C atoms at the TL front.