Hi Guenter,

Would you (or someone) please explain or point me to an explanation of
"Rest-eutectic"? I (and I'm certain, others) am unfamiliar with this term.

Regards,

Ed Popielarski
QTA Machine
27291 Jardines
Mission Viejo, Ca 92692

Ph: 949-581-6601

WWW.QTA.NET



You see, wire telegraph is a kind of a very, very long cat. You pull his tail
in New York and his head is meowing in Los Angeles. Do you understand this?
And radio operates exactly the same way: you send signals here, they receive
them there. The only difference is that there is no cat.

Albert Einstein (1879 - 1955), when asked to describe radio

********

Date:    Mon, 30 May 2005 09:00:10 +0200
From:    Guenter Grossmann [log in to unmask]
Subject: Antw: [TN] micro cracks in leadfree wavesolder

Ken,

No I haven't read a paper, but these microcracks are frequently seen in our
lab in failure analysis. They occur due to 3 reasons (as far as I know):

- 2 Solidification fronts meeting each other and being already too cold to
join. I believe that this is mainly a design problem.

- Shrinking of the rest- eutectic between the Sn dendrites
- Well I believe that a SnBiPb rest- eutectic is rare nowadays

Best regards

Guenter

EMPA

Swiss Federal Laboratories  for Materials Testing and Research Centre for
Reliability Guenter Grossmann,  Senior Engineer

8600 Duebendorf
Switzerland

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

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