Microstructural Evaluation and Comparison of Solder Samples Processed Aboard the International Space Station
- Paper number
IAC-08.A2.6.A9
- Author
Dr. Richard Grugel, National Aeronautics and Space Administration (NASA)/Marshall Space Flight Center, United States
- Coauthor
Dr. Fay Hua, Intel Corporation, United States
- Coauthor
Dr. A. Anilkumar, Vanderbilt University, United States
- Year
2008
- Abstract
Samples from the In-Space Soldering Investigation (ISSI) that was conducted aboard the International Space Station (ISS) are in the process of being examined to reveal post-solidification microstructural development and porosity distribution. For this presentation the internal structures of two ISSI processed samples have been compared. In one case 10cm of rosin-core solder was wrapped around a coupon wire and melted by conduction, whereas, in the other a comparable length of solder was melted directly onto the hot wire; in both cases the molten solder formed ellipsoidal blobs, a shape that was maintained during subsequent solidification. In the former case, there is clear evidence of porosity throughout the sample, and an accumulation of larger pores near the hot end that implies thermocapillary induced migration of the flux vapors. In the second context, when solder is fed onto the wire, the majority of flux comprising the solder core is introduced into and remains within the liquid solder ball, becoming entombed upon solidification. In both cases the consequential porosity, particularly at a solder/contact interface, is very undesirable as, in addition to compromising the desired electrical and thermal conductivity, it promotes mechanical failure.
- Abstract document
- Manuscript document
(absent)