posted on 2008-10-22, 14:13authored byJianfeng Li, Samjid H. Mannan, Mike P. Clode, Keming Chen, David C. Whalley, David A. Hutt, Paul ConwayPaul Conway
This paper reports on the interfacial reactions and lifetime of electroless Ni-P coatings in contact with molten Sn-Bi based solders. A layer of approximately 4 m thick electroless Ni-P in contact with the molten Sn-58Bi solder began to fail at 48 h at
temperatures between 200 C and 240 C. Elemental additions to modify the solder, included 1–2wt.% of Al, Cr, Si, Zn, Ag, Au, Ru, Ti, Pt, Nb, and Cu. Of these, only Cu modified the interfacial intermetallic
compound growth from Ni3Sn4 to (Cu,Ni)6Sn5, resulting in significantly decreased consumption rates of the Ni-P substrate
in contact with the molten solder and increasing the lifetime of the Ni-P layer to between 430 and 716 h. Micro cracks were observed in all but the thinnest Ni-P layers, allowing the solder to penetrate.
History
School
Mechanical, Electrical and Manufacturing Engineering
Citation
LI, J. ...et al, 2008. Interfacial reaction between molten Sn-Bi based solders and electroless Ni-P coatings for liquid solder interconnects. transactions on components and packaging technologies, 31 (3), pp. 574 – 585