, Volume 21, Issue 5, pp 606-613,
Open Access This content is freely available online to anyone, anywhere at any time.
Date: 09 Mar 2012

Wetting of Cu and Al by Sn-Zn and Zn-Al Eutectic Alloys

Abstract

Wetting properties of Sn-Zn and Zn-Al alloys on Cu and Al substrates were studied. Spreading tests were carried out for 3 min, in air and under protective atmosphere of nitrogen, with the use of fluxes. In the case of Zn-Al eutectic, spreading tests were carried out at 460, 480, 500, and 520 °C, and in the case of Sn-Zn eutectic at 250, 300, 350, 400, 450, and 500 °C, respectively. Solidified solder/substrate couples were cross-sectioned and subjected to microstructure examination. The spreading tests indicated that the wetting properties of eutectic Sn-Zn alloys, on copper pads do not depend on temperature (up to 400 °C), but in the lack of protective atmosphere, the solder does not wet the pads. Wettability studies of Zn-Al eutectic on aluminum and copper substrates have shown a negative effect of the protective nitrogen atmosphere on the wetting properties, especially for the copper pads. Furthermore, it was noted that with increasing temperature the solder wettability is improved. In addition, densities of liquid solders were studied by means of dilatometric technique.

This article is an invited submission to JMEP selected from presentations at the Symposia “Wetting, soldering and brazing” and “Diffusion bonding and characterization” belonging to the Topic “Joining” at the European Congress and Exhibition on Advanced Materials and Processes (EUROMAT 2011), held September 12-15, 2011, in Montpellier, France, and has been expanded from the original presentation.