>    Im looking at etchants for microstructural analysis
> of 63/37 Sn/Pb solder joints. i had used Hydrogen
> peroxide and Ammonium hydroxide for the etchign but
> still the SEM image does not clearly distinguish the
> Tin and lead matrix. Can anybody suggest ways to
> clearly distinguish the metallurgy and the
> intermetallics?
>

Buehler has a technical note for sectioning and sample preparation of
solders:
  http://www.buehler.com/application_support/tech_note_pdf/vol1_issue7.pdf
(you might have to create an account in their Technical Information to get
to this document.

I have a book edited by John H. Lau, "Solder Joint Reliability", which has
some great pictures in Chapter 6 (written by James L. Marshall). They
recommend looking at both backscattered and secondary images if you can.
They also refer to Buehler for literature on sample prep, as well as:
        M. McLean, Directionally solidified eutectics, The Metals Society,
London,
1983.
        P.G. Shewmon, Transformations in Metals, J. Williams Book Co., OK, 1983.
        R. Elliot, Eutectic solidification processing, Butterworths, London,
1983.
        J.D. Verhoeven et al, Met Trans A, 8A, 1977. pp. 1239-1247.
        J.D. Hunt, J Inst Met, 94, 1964, pp. 125-129.

Bill Eaton, Ph.D.
Materials & Analysis Manager
NP Photonics
bill@npphotonics.com