, Volume 21, Issue 5, pp 599-605,
Open Access This content is freely available online to anyone, anywhere at any time.

Thermal Properties and Wetting Behavior of High Temperature Zn-Al-In Solders

Abstract

Solders for ultrahigh-temperature applications were defined by Vianco as those able to sustain working conditions with temperatures as high as 573 K, with momentary temperature rise up to 623 K. Zn-Al eutectic alloy (12 at.% Al) fits such defined criteria with respect to its melting temperature. It was found that small additions of indium to Zn-Al eutectic lower its melting temperature. The aim of this work is to assess if and to what extent thermal properties and wetting behavior are affected. It was found that addition of In increases electrical resistivity and coefficient of thermal expansion value. Wetting angles on Cu and Al substrates of liquid Zn-Al eutectic-based alloys containing up to 1.5 at.% of In were studied with the sessile drop method, after wetting at 773 K in the presence of flux. A decrease of apparent wetting angle was observed with increasing concentration of In. After wetting tests solidified alloy-substrate couples were cross-sectioned and examined with scanning electron microscopy coupled with electron dispersive X-ray analysis.

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.