Metastable eutectic in Pb-free joints between Sn-3.5Ag and Ni-based substrates
Author(s)
Belyakov, SA
Gourlay, CM
Type
Journal Article
Abstract
Microstructure development in solder joints between Sn
–
3.5Ag and Ni-based substrates has been widely
reported. However, in the present study we illustrate a new phenomenon: that during soldering of
Sn
–
3.5Ag to Ni or ENIG (electroless nickel, immersion gold), the bulk solder solidi
fi
es to contain a
metastable eutectic consisting of
β
Sn
þ
Ag
3
Sn
þ
NiSn
4
instead of the
β
Sn
þ
Ag
3
Sn
þ
Ni
3
Sn
4
, expected of
equilibrium solidi
fi
cation. It is shown that metastable NiSn
4
coarsens and then decomposes into Ni
3
Sn
4
and
β
Sn during aging at 150 and 200
1
C and that coarsened NiSn
4
particles deteriorate impact shear
properties.
–
3.5Ag and Ni-based substrates has been widely
reported. However, in the present study we illustrate a new phenomenon: that during soldering of
Sn
–
3.5Ag to Ni or ENIG (electroless nickel, immersion gold), the bulk solder solidi
fi
es to contain a
metastable eutectic consisting of
β
Sn
þ
Ag
3
Sn
þ
NiSn
4
instead of the
β
Sn
þ
Ag
3
Sn
þ
Ni
3
Sn
4
, expected of
equilibrium solidi
fi
cation. It is shown that metastable NiSn
4
coarsens and then decomposes into Ni
3
Sn
4
and
β
Sn during aging at 150 and 200
1
C and that coarsened NiSn
4
particles deteriorate impact shear
properties.
Date Issued
2015-02-21
Date Acceptance
2015-02-14
Citation
Materials Letters, 2015, 148, pp.91-95
ISSN
1873-4979
Publisher
Elsevier
Start Page
91
End Page
95
Journal / Book Title
Materials Letters
Volume
148
Copyright Statement
© 2015 Elsevier B.V. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000353097100023&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
EP/M002241/1
Subjects
Science & Technology
Technology
Physical Sciences
Materials Science, Multidisciplinary
Physics, Applied
Materials Science
Physics
Microstructure
Intermetallic compounds
Eutectic solidification
Lead-free solder
Electronic packaging
Aging
SN/NI INTERFACIAL REACTIONS
LEAD-FREE SOLDERS
INTERMETALLIC COMPOUND
NISN4 FORMATION
SN
TEMPERATURE
METALLIZATION
RELIABILITY
NUCLEATION
GROWTH
Materials
09 Engineering
03 Chemical Sciences
Publication Status
Published