It is desirable, where practicable, to remove lead-containing components from commercial products for
environmental considerations. One area where lead is extensively used is in lead-based solders. New lead-free
solders must have the appropriate melting temperatures and freezing ranges, in order to be compatible with
existing equipment and components. A thermodynamic database can be used to predict these properties and also
show the effects of non-equilibrium solidification. The results from these predictions can be used to
eliminate candidate solder alloys for which the calculation revealed unsuitable freezing temperature and
range from further testing.
Different types of calculated systems must be distinguished:
- Assessed systems: A critical evaluation of available experimental data was used to derive a
termodynamic description of the multicomponent system. If experimental data were only available or considered
for part of the system then a partial assessment is possible.
- Extrapolated systems: The analytical descriptions of contistuent subsystems are combined and used
to predict the multicomponent system, even for compositions and temperatures which have not been
experimentally evaluated. Depending on the complexity of the multicomponent system this prediction will be
more or less accurate.
This webpage contains a collection of calculated binary and ternary systems that are relevant to solders.
The thermodynamic descriptions of these systems are compiled in database files which can be downloaded.
Examples for the application of these systems can be found in our papers on solders.
Binary Systems
Ternary Systems
Thermodynamic Database (Sn - Ag - Bi - Cu - Pb)
Condensed Phases
Phase |
Struktur-
bericht
Symbol |
Common Names |
Prototype |
Spacegroup |
Model* |
|
Liquid |
n/a |
L, L1,L2 |
n/a |
n/a |
(Ag,Bi,Cu,Pb,Sn)1 |
|
Fcc |
A1 |
(Ag), (Cu), (Pb) |
Cu |
Fm-3m |
(Ag,Bi,Cu,Pb,Sn)1(Va)1 |
Bcc |
A2 |
(beta Cu) |
W |
Im-3m |
(Cu,Sn)1(Va)3 |
Hcp |
A3 |
(zeta Ag), (epsilon Pb) |
Mg |
P63/mmc |
(Ag,Bi,Pb,Sn)1(Va)0.5 |
Bct |
A5 |
(Sn), (beta Sn) |
beta Sn |
I41/amd |
(Ag,Bi,Cu,Pb,Sn)1 |
Rho |
A7 |
(Bi) |
alpha As |
R-3m |
(Bi,Pb,Sn)1 |
|
Ag3Sn |
D0alpha |
epsilon |
beta Cu3Ti |
Pmmn |
(Ag)0.75(Sn)0.25 |
Cu3Sn.h |
D03 |
gamma |
BiF3 |
Fm-3m |
(Cu,Sn)0.75(Cu,Sn)0.25 |
Cu41Sn11 |
... |
delta |
... |
F-43m |
Cu0.788Sn0.212 |
Cu10Sn3 |
... |
zeta |
... |
P63 |
Cu0.769Sn0.231 |
Cu3Sn |
... |
epsilon |
... |
Cmcm |
Cu0.75Sn0.25 |
Cu6Sn5 |
B81 |
eta,
Cu6Sn5.h |
NiAs |
P63/mmc |
Cu0.545Sn0.455 |
Cu6Sn5' |
... |
eta ',
Cu6Sn5.l |
... |
... |
Cu0.545Sn0.455 |
*Major species are printed bold face
Thermodynamic Database Files
|