Wetting behaviour and interfacial microstructure of Sn-Ag-Zn solder alloys on nickel coated aluminium substrates

• Published in: Materials science and technology Vol. 27; no. 7; pp. 1157 - 1162
• Main Authors: Satyanarayan, Prabhu, K N
• Format: Journal Article
• Language: English
• Published: London, England Taylor & Francis 01.07.2011; SAGE Publications; Taylor & Francis Ltd
• Subjects: Aluminium; Aluminum; Contact angle; IMCs; Intermetallic compounds; Lead free solders; Mathematical analysis; Microstructure; Nickel; Solders; Substrates; Tin; Wettability; Wetting; Work of adhesion; Wettability; Contact angle; Lead free solders; Work of adhesion; IMCs
• ISSN: 0267-0836; 1743-2847
• DOI: 10.1179/026708310X12815992418337

Wetting behaviours of two lead free solders (Sn-2·625Ag-2·25Zn and Sn-1·75Ag-4·5Zn) on nickel coated aluminium substrates were investigated. Sn-2·625Ag-2·25Zn exhibited better wettability compared to Sn-1·75Ag-4·5Zn solder. Contact angles of the solders increased with increasing roughness of the substrate. The Young-Dupre equation was used to evaluate the work of adhesion of solder on the substrate. Sn-2·625Ag-2·25Zn solder exhibited higher work of adhesion than Sn-1·75Ag-4·5Zn. A thin continuous layer of Ni 3 Sn was detected at the interface between Sn-2·625Ag-2·25Zn solder and nickel coated Al substrate. Sn-1·75Ag-4·5Zn solder exhibited scallop intermetallic compounds (IMCs) growing into the solder field as well as a thin continuous IMC in some cases. Ni 3 Sn and Ni 3 Sn 4 IMCs were observed at the interface of Sn-1·75Ag-4·5Zn solder and nickel coated Al.