Kirk

Two possies I know of for dull Pb free solder:

- Intermetallics swimming on the surface of the liquid solder.

- Shrink cracks along primarily solidified phases. These cracks are not deep. They form because SnAg phases solidify like dendrites leaving a certain amount of liquid solder so that a gap forms when the solder joint cools down. Eric reported about this not eutectic solidification.

Have a great day


Guenter

Guenter Grossmann
Swiss Federal Institute for Materials Testing and Research EMPA
Centre for Reliability
8600 Duebendorf
Switzerland

Phone: xx41 1 823 4279
Fax :      xx41 1823 4054
mail:     [log in to unmask]

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