LAUSR

Abstract The wetting of molten Sn-3.5Ag-0.5Cu alloy on the Ni-P(-SiC) coated SiCp/Al substrates was investigated by electroless Ni plating process, and the microstructures of the coating and the interfacial behavior of wetting systems were analyzed. The SiC particles are evenly distributed in the coating and enveloped with Ni. No reaction layer is observed at the coating/SiCp/Al composite interfaces. The contact angle increases from ∼19° with the Ni-P coating to 29°, 43° and 113° with the corresponding Ni-P-3SiC, Ni-P-6SiC and Ni-P-9SiC coatings, respectively. An interaction layer containing Cu, Ni, Sn and P forms at the Sn-Ag-Cu/Ni-P-(0,3,6)SiC coated SiCp/Al interfaces, and the Cu-Ni-Sn and Ni-Sn-P phases are detected in the interaction layer. Moreover, the molten Sn-Ag-Cu can penetrate into the Ni-P(-SiC) coatings through the Ni-P/SiC interface and dissolve them to contact the SiCp/Al substrate.