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Title: Measurement of Sn and In Solidification Undercooling and Lattice Expansion Using In Situ X-Ray Diffraction

The solidification behavior of two low-melting-point metals, Sn and In, on three substrates has been examined using in situ x-ray diffraction. Undercoolings of up to 56.1°C were observed for Sn solidified on graphite, which is a non-wetting substrate, while lower undercoolings were observed for Sn on Au/Ni/Cu (17.3°C) and on Cu (10.5°C). Indium behaved quite differently, showing undercoolings of less than 4°C on all three substrates. The lattice expansion/contraction behavior of Sn, In, and intermetallic compounds (IMCs) that formed during the reaction of Sn with Au/Ni/Cu surfaces were also measured during heating and cooling. Results showed anisotropic and nonlinear expansion of both Sn and In, with a contraction, rather than expansion, of the basal planes of In during heating. The principal IMC that formed between Sn and the Au/Ni/Cu surface was characterized as Cu 6Sn 5, having an average expansion coefficient of 13.6 × 10 ₋6/°C, which is less than that of Sn or Cu.
 [1] ;  [2]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0361-5235
Grant/Contract Number:
AC52-07NA27344; AC05- 00OR22725; W-31-109-ENG-38
Accepted Manuscript
Journal Name:
Journal of Electronic Materials
Additional Journal Information:
Journal Volume: 40; Journal Issue: 2; Journal ID: ISSN 0361-5235
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
36 MATERIALS SCIENCE; In situ x-ray diffraction; solidification, nucleation; undercooling; Sn; In; lead-free solders; wetting; nonlinear expansion; intermetallic compounds; synchrotron radiation
OSTI Identifier: