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Synthesis, characterization, antioxidant, cytotoxic, and DNA cleavage studies of ruthenium(III) complexes containing N-substituted thiosemicarbazone/semicarbazone
Monatsh Chem (2012) 143:1275–1287
DOI 10.1007/s00706-012-0737-1
ORIGINAL PAPER
A new experimental phase diagram investigation of Cu–Sb
Siegfried Fürtauer • Hans Flandorfer
Received: 16 January 2012 / Accepted: 9 February 2012
Ó The Author(s) 2012. This article is published with open access at Springerlink.com
Abstract The binary system Cu–Sb is a constituent system that is studied in investigations of technically
important ternary and quaternary alloy systems (e.g.,
casting alloys and lead-free solders). Although this binary
system has been thoroughly investigated over the last
century, there are still some uncertainties regarding its
high-temperature phases. Thus, parts of its phase diagram
have been drawn with dashed lines in reviews published in
the literature. The aim of this work was to resolve these
uncertainties in the current phase diagram of Cu–Sb by
performing XRD, SEM-EDX, EPMA, and DTA. The
results from thermal analysis agreed well with those given
in the literature, although some modifications due to the
invariant reaction temperatures were necessary. In particular,
reactions located on the Cu-rich side of the nonquenchable
high-temperature b phase (BiF3-type) left considerable scope
for interpretation. Generally, the structural descriptions of
the various binary phases given in the literature were verified. The range of homogeneity of the e phase (Cu3Ti type)
was found to be higher on the Sb-rich side. Most of the
reaction temperatures were verified, but a few had to be
revised, such as the eutectoid reaction b ! e þ g at
440 °C (found to occur at 427 °C in this work) and the
eutectoid reaction c ! ðCuÞ þ d at 400 °C (found to occur
at 440 °C in this work). Further phase transformations that
had previously only been estimated were confirmed, and
their characteristic temperatures were determined.
Dedicated to O. Prof. Dr. Herbert Ipser on the occasion of his 65th
birthday.
S. Fürtauer H. Flandorfer (&)
Department of Inorganic Chemistry/Materials Chemistry,
University of Vienna, Währingerstraße 42, 1090 Vienna, Austria
e-mail: hans.flandorfer@univie.ac.at
Keywords Phase diagrams Phase transitions
X-ray structure determination Thermodynamics
Introduction
Lead-free soldering
Compared to, say, lead–acid accumulators, solders used in
electronics utilize only a relatively small proportion of the lead
consumed worldwide. However, recycling lead from electronic waste is a complicated task, and it pollutes the
environment when deposited in landfills and incinerator
plants. In the European Union, the use of lead-containing
solders has been prohibited since 2006, although there are
unfortunately many exceptions for special applications. The
electronics industry has therefore tried to phase-in the use of
solders containing other, less harmful, materials than lead over
the last decade. While the development of lead-free lowtemperature soft solders (melting point *180–230 °C) is
fairly advanced, research into lead-free high-temperature soft
solders (melting range [230–350 °C) is still in progress. In
order to perform a systematic search for appropriate alloy
systems, some fundamental data on phase relations and thermochemical properties are essential. COST Action MP0602
will lead to the creation of an encyclopedic database containing data on several different binary and ternary alloy
systems. Alloy systems containing the components of leadfree solder and substrate materials are of particular interest for
inclusion in this database. The Cu–Sb system is a possible
binary constituent of lead-free solder systems. Indeed, Sb is a
component of some lead-free solders that are already available
on the market (e.g., Ag–Sb–Sn or Cu–Sb–Sn), and copper is
the most commonly used substrate, as well as a potential
component of the solder itself.
123
1276
Despite the fact that there is already a considerable
amount of data on the Cu–Sb system, some ambiguities
were noticed when a literature search focusing on this
system was performed. This primarily affects the hightemperature phase (b phase, BiF3 type), which cannot be
stabilized at room temperature by quenching. Thus, the aim
of the work described in the present paper was to improve
the current version of the phase diagram for the Cu–Sb
system by incorporating data gained from new experiments
and by critically assessing the available data in the relevant
literature. This work will therefore contribute valuable
information to the lead-free solder database and lead to
better thermodynamic descriptions of this binary system
(see [1, 2]) and derived higher-order systems via the
CALPHAD approach.
Literature review
The Cu–Sb phase diagram, as drawn in Massalski [3], is
presented in Fig. 1. Invariant reactions are listed in Table 1
and crystallographic data in Table 2, which were taken
from works by several authors (see [4–11]).
The a phase is Cu containing Sb with extended solubility. The maximum solubility of Sb occurs at 5.8 at% Sb
and 645 °C. In contrast to this, there is nearly no solubility
of Cu in Sb. The b phase, which is a high-temperature
phase, melts congruently at 683 °C. It crystallizes in a
cubic BiF3-type structure (DO3) with the space group Fm3m. At the liquid melt, the Sb-rich b forms the g phase in a
Fig. 1 Current version of the
phase diagram of the Cu–Sb
system [3]
123
S. Fürtauer, H. Flandorfer
peritectic reaction (586 °C). On the Cu-rich side, b and
(Cu) are formed eutectically at 645 °C. The b phase
decomposes in a eutectoid reaction at 440 °C into e and g.
Schubert and Illschner first published this reaction [12],
and Heumann and Heinemann [13] subsequently proposed
the eutectoid reaction b ! d þ e at 436 °C and 22.3 at%
Sb based on micrographic data. However, Hansen [14] and
later Massalski [3] did not consider the work of Heumann
and Heinemann in their assessments, instead establishing
the eutectoid decomposition e ! d þ g at 375 °C, which
was also determined by micrographic data from Heumann
Table 1 Temperature-invariant reactions in the Cu–Sb system [1]
Reaction
Composition /at% Sb
L!b
29
Temp. /°C Reaction type
683
Congruent melt
L ! ðCuÞ þ b
5.8
19
19.5
645
Eutectic
Lþb!g
L ! g þ ðSbÞ
31
33.5
33.5
63
46
99.9
586
526
Peritectic
Eutectic
ðCuÞ þ b ! c
5.65
15.5
21.5
488
Peritectoid
bþc!d
16.5
19
24
462
Peritectoid
bþd!e
19.5
23
25.5
445a
Peritectoid
b!eþg
25.5
26.5
32
440a
Eutectoid
c ! ðCuÞ þ d
4.6
15.5
18.5
400
Eutectoid
dþe!f
20
21.5
23.5
390a
Peritectoid
e!fþg
22.5
24
32.5
360
Eutectoid
f!dþg
20
21.5
32.5
260a
Eutectoid
a
Uncertain values
A new experimental phase diagram investigation of Cu–Sb
1277
Table 2 Crystallographic data for Cu–Sb phases
Phase
Stoichiometry
Type
Pearson symbol
Space group
No.
a /Å
b /Å
c /Å
Ref.
a
(Cu)
Cu
cF4
Fm-3m
225
3.6130
–
–
[4]
b
Cu3Sb
BiF3
cF16
Fm-3m
225
6.0000
–
–
[5]
c
Cu4Sb
Mg
hP2
P63/mmc
194
2.7520
–
4.3200
[6]
[7]
d
Cu78Sb20
Cu78Sb21
hP98
P63/mmc
194
19.124
–
4.324756
e
Cu3Sb
Cu3Ti
oP8
Pmmn
59
5.5040
4.3530
4.7680
[8]
f
Cu10Sb3
Cu10Sb3
hP26
P-3
147
9.9200
–
4.3200
[9]
g
Cu2Sb
Cu2Sb
tP6
P4/nmm
129
4.0014
–
6.1044
[10]
h
(Sb)
As
hR2
R-3m
166
4.3084
–
11.2740
[11]
and Heinemann’s work [13]. Later, Günzel and Schubert
[15] described a new phase (f) occurring on the Sb-rich
side of d. Therefore, the latter reaction had to be corrected
to e ! f þ g (adjusted from 375 to 360 °C). The c phase is
formed from the b phase with (Cu) in the peritectoid
reaction ðCuÞ þ b ! c (488 °C). This transformation and
the peritectoid reaction c þ b ! d (462 °C) were found by
Murakami and Shibata [16], and both were confirmed by
Schubert and Ilschner [12] using dilatometric methods. The
e phase was first mentioned by the same authors. They
tentatively fixed the respective reaction temperatures and
the concentration limits according to their high-temperature X-ray diffraction results. The invariant peritectoid
temperatures of the reactions b þ d ! e (445 °C) and
d þ e ! f(390 °C) as well as the eutectoid decomposition
of f (f ! d þ g, 280 °C) were only roughly estimated by
Günzel and Schubert [15] from X-ray diffraction experiments. They proposed the peritectoid temperature
(d þ e ! f) to be 390 °C, but due to the scatter in their
experimental data it can only be said to occur in the temperature range 375–400 °C. The decomposition temperature
(f ! d þ g) is suggested to be 260 °C, but again this
temperature can only be stated to lie between 250 and
300 °C. The experimental evidence for the eutectoid reaction c ! ðCuÞ þ d at 400 °C as presented in the phase
diagrams of Hansen [14] and Massalski [3] is unknown.
Thus, some reaction temperatures and phase homogeneity
ranges are tentative and not determined precisely yet. This is
shown by dashed lines in the assessment of the Cu–Sb system
by Massalski [3]. Further works by Liu et al. [2] in 2000
and Gierlotka et al. [1] in 2009 contribute thermodynamic
assessments with similar transition temperatures to
those described by Massalski [3]. These works are the most
recent ones; nevertheless, information on the ranges of
homogeneity of many phases is missing. Liu et al. [2]
modeled the liquid, the (Cu), the (Sb), and the b phases as
solid solutions, as did Gierlotka et al. [1], but the latter also
calculated the d and the c phases as sublattice models. The
results obtained in the present work are compared with those
given in [3].
Results and discussion
The samples used for DTA measurements were annealed
for four weeks at 340 °C or six months at 170 °C and
quenched in cold water. The temperature program included
two heating and cooling loops, starting from the annealing
temperature and ending 50–100 °C above the estimated
liquidus temperature. The heating rate was 5 K/min, the
measured temperatures are summarized in Table 3, the
DTA curves can be found in Fig. 2, and the corresponding
invariant reactions are listed in Table 4. In addition, we
generally performed measurements with heating rates of
10 K/min in order to observe the influence of the heating
rate on the characteristic temperatures. There was no significant change in the transition temperatures when the
heating rate was increased. The temperatures of the maxima of the melting peaks of all samples are consistent with
the liquidus temperatures given in [3]. The solidus of the b
phase, which was established by performing DTA measurements of five samples with 21–28 at% Sb, was also in
agreement with the literature [3]. The reaction temperature
as well as the liquidus concentration of 19 at% Sb for the
eutectic reaction located at 645 °C (L ! ðCuÞ þ b) were
confirmed based on three of our samples; see Table 3.
However, samples at 10, 17.5, and 19.5 at% Sb showed
some discrepancies from the data in the literature at temperatures below 645 °C [3]. Strong effects were observed
in all three samples at temperatures of 467 and 484 °C. We
allocated the effect at 467 °C to the reaction b þ c ! d,
which is described in the literature as occurring at 462 °C
[3], and the effect at 484 °C to ðCuÞ þ b ! c (which takes
place at 488 °C according to the literature [3]). However,
according to the phase relations [3], the effect at 467 °C
should not be observable in the sample with 10 at% Sb in
the first heating run. Surprisingly, this effect was even
stronger in the second heating run. In order to clarify this
discrepancy, we annealed this sample at 470 and 480 °C
for 28 days. Both temperatures resulted in large amounts of
(Cu) and c, but also traces of the b phase (see Tables 5, 6).
It is worth noting at this point that the b phase cannot be
123
1278
S. Fürtauer, H. Flandorfer
Table 3 Summary of measured thermal effects
No.
Nominal comp. /at%
Heat treatment
Thermal analysis
Heating /°C
Invariant effects
Cooling /°C
Other effects
Liquidus
Liquidus
1
Cu90Sb10
340 °C, 28 days
469, 482.2, 642.2
926.1
920.6
2
Cu82.5Sb17.5
340 °C, 28 days
440, 467.1, 485, 644.9
651.5
642.2
3
4
Cu80.5Sb19.5
Cu79Sb21
340 °C, 28 days
340 °C, 28 days
461.8, 486.8
443.5, 451.9
650.9
654.6
641.4
647.5
5
Cu77.5Sb22.5
340 °C, 28 days
360.5, 441.4
648.9
660.8
655.2
6
Cu76Sb24
170 °C, 6 months
(323.3)a, 363.3
436.8, 655
670.6
665.9
7
Cu74Sb26
170 °C, 6 months
(302.3)a, 375.8, 431.9
668.9
681.6
675.0
641.8
644.2
8
Cu72Sb28
340 °C, 28 days
428.6
433.8, 679.7
690.2
679.3
9
Cu70Sb30
Melt
426.7
470.3, 673.1
686.3
676.7
10
Cu60Sb40
340 °C, 28 days
525.8, 586.2
616.0
597.3
11
Cu35Sb65
340 °C, 28 days
524.8
539.9
506.6
12
Cu30Sb70
340 °C, 28 days
525.4
546.4
518.2
13
Cu25Sb75
340 °C, 28 days
526.5
553.9
517.7
a
Very weak effect
Fig. 2 DTA curves of samples with 10–40 at% Sb
quenched; it mainly decomposes to the low-temperature
phases d and e. Thus, we instead assume that (Cu) is in
equilibrium with c at both temperatures. Although the
effect is clearly present at 467 °C in the sample with 10
at% Sb, we have decided not to change the previously
accepted phase diagram given in the literature [3]. XRD
analysis of Cu90Sb10 annealed at 435 °C and Cu82.5Sb17.5
annealed at 430 °C showed (Cu) and d as equilibrium
phases (see Fig. 3). According to the literature, these
samples should both contain the c phase [3]. Supported by
an invariant reaction observed at 440 °C during DTA of
Cu82.5Sb17.5, we fixed the eutectoid reaction c ! ðCuÞ þ d
at this temperature. This is additionally supported by the
123
fact that the original source of the reaction temperature of
400 °C given in [3] could not be found and thus appears to
be estimated. The peritectoid reaction b þ d ! e was
corroborated by DTA of samples with 21 and 22.5 at% Sb.
However, the corresponding temperature (440 °C) differs
slightly from the literature value (445 °C [3]). DTA of
these samples should also show invariant reactions
according to e þ d ! f (390 °C) and e ! f þ g (360 °C),
and we did indeed find the reaction at 360 °C in
Cu87.5Sb22.5 as a weak effect in the second heating run.
However, we could not locate the peritectoid reaction at
390 °C. Thermal analysis of the samples with 24 and 26
at% Sb agreed well with the previously reported phase
diagram [3] above 350 °C. On the other hand, DTA of
samples annealed at 170 °C did not indicate the invariant
reaction at 260 °C f ! d þ g. Instead, we found two further signals at different temperatures that are possibly
related to this reaction (24 at% Sb 323 °C, 26 at% Sb
302 °C; see also Table 3). Because XRD data for the
samples with 21, 22.5, 24, and 26 at% Sb are consistent
with the literature data [3], we kept the previously reported
phase relations and reaction temperatures. Using the samples with 28 and 30 at% Sb, we were able to determine the
temperature of the eutectoid reaction b ! e þ g as 427 °C,
which had previously been estimated as 440 °C ([3]:
dashed lines, see Fig. 1). The liquidus and solidus
curves allowed us to estimate the congruent melting point
of the b phase at 690 °C and 29 at% Sb ([3], 683 °C).
Finally, we also verified the eutectic reaction at 526 °C
(L ! g þ ðSbÞ) and the peritectic reaction at 586 °C
(b þ L ! g).
A new experimental phase diagram investigation of Cu–Sb
1279
Table 4 Comparison of reactions and temperatures published in the literature and found in this work
Invariant reactions
Temp. /°C: [1]
Temp. /°C: this work
Comments
L!b
683
690
Estimated from liquidus curves
L ! ðCuÞ þ b
645
645
Lþb!g
586
586
L ! g þ ðSbÞ
526
526
ðCuÞ þ b ! c
488
484
bþc!d
462
467
bþd!e
445
440
b!eþg
440
427
c ! ðCuÞ þ d
400
440
dþe!f
390
390
Not detected, adopted from literature
e!fþg
f!dþg
360
260
360
260
Not detected, adopted from literature
Table 5 Crystal structures and lattice parameters of quenched Cu–Sb samples
Sample
Heat treatment
Phase
Cu90Sb10
Melt 1,000 °C, 1 day a = (Cu)
Structure Lattice parameter /Å
type
Comment
Fm-3m
Nonequilibrium (quenched from liquid)
a = 3.662(4)
d = Cu78Sb20 P63/mmc a = 19.035(3), c = 4.3285(9)
340 °C, 28 days
a = (Cu)
Fm-3m
a = 3.64479(2)
d = Cu78Sb20 P63/mmc a = 19.0823(2), c = 4.32615(9)
390 °C, 28 days
a = (Cu)
Fm-3m
a = 3.65393(6)
d = Cu78Sb20 P63/mmc a = 19.0421(4), c = 4.3260(2)
420 °C, 28 days
a = (Cu)
Fm-3m
a = 3.66266(7)
d = Cu78Sb20 P63/mmc a = 19.0286(5), c = 4.3291(2)
435 °C, 28 days
a = (Cu)
Fm-3m
a = 3.66487(9)
d = Cu78Sb20 P63/mmc a = 19.0074(4), c = 4.3281(1)
450 °C, 28 days
470 °C, 28 days
480 °C, 28 days
600 °C, 28 days
a = (Cu)
Fm-3m
c = Cu4Sb
P63/mmc a = 2.68573(9), c = 4.3274(3)
a = (Cu)
Fm-3m
a = 3.62263(2)
b = Cu3Sb
Fm-3m
a = 5.8105(1)
a = 3.6686(1)
c = Cu4Sb
P63/mmc a = 3.3521(3), c = 2.8928(5)
a = (Cu)
Fm-3m
a = 3.6719(1)
b = Cu3Sb
Fm-3m
a = 5.9162(9)
c = Cu4Sb
P63/mmc a = 2.7527(4), c = 4.244(2)
a = (Cu)
Fm-3m
c = Cu4Sb
P63/mmc a = 2.74168(8), c = 4.3304(2)
b phase partially stabilized
b phase partially stabilized
a = 3.67907(7)
d = Cu78Sb20 P63/mmc a = 19.101(3), c = 4.3307(8)
Cu82.5Sb17.5 Melt 1,000 °C, 1 day d = Cu78Sb20 P63/mmc a = 19.1198(4), c = 4.3273(1)
340 °C, 28 days
e = Cu3Sb
Pmmn
a = 5.5045(3), b = 4.3355(2), c = 4.7549(4)
a = (Cu)
Fm-3m
a = 3.6482(9)
Nonequilibrium (quenched from liquid)
d = Cu78Sb20 P63/mmc a = 19.0836(1), c = 4.32763(4)
430 °C, 28 days
a = (Cu)
Fm-3 m
a = 3.6676(7)
d = Cu78Sb20 P63/mmc a = 18.9911(2), c = 4.32639(8)
470 °C, 28 days
c = Cu4Sb
P63/mmc a = 2.69586(9), c = 4.3309(3)
d = Cu78Sb20 P63/mmc a = 19.0113(5), c = 4.3278(2)
600 °C, 28 days
a = (Cu)
Fm-3m
a = 3.6805(4)
b = Cu3Sb
Fm-3m
a = 5.9239(5)
b phase partially stabilized
d = Cu78Sb20 P63/mmc a = 19.1485(3), c = 4.3291(1)
123
1280
S. Fürtauer, H. Flandorfer
Table 5 continued
Sample
Heat treatment
Phase
Structure type Lattice parameter /Å
Cu80.5Sb19.5 340 °C, 28 days
d = Cu78Sb20 P63/mmc
a = 19.1178(1), c = 4.32590(6)
Cu79.5Sb20.5 170 °C, 6 months
d = Cu78Sb20 P63/mmc
a = 19.1241(5), c = 4.3279(1)
f = Cu10Sb3
P-3
a = 9.9335(1), c = 4.3227(1)
g = Cu2Sb
P4/nmm
280 °C, 28 days
d = Cu78Sb20 P63/mmc
350 °C, 28 days
d = Cu78Sb20 P63/mmc
420 °C, 28 days
d = Cu78Sb20 P63/mmc
f = Cu10Sb3
f = Cu10Sb3
e = Cu3Sb
Cu79Sb21
P-3
P-3
Pmmn
Melt 1,000 °C, 1 day d = Cu78Sb20 P63/mmc
a = 5.493(2), b = 4.3468(2), c = 4.757(2)
a = 19.1665(8), c = 4.3317(3)
f = Cu10Sb3
P-3
d = Cu78Sb20 P63/mmc
a = 19.1082(2), c = 4.32665(9)
e = Cu3Sb
Pmmn
a = 5.4920(2), b = 4.34468(8), c = 4.7510(2)
470 °C, 28 days
b = Cu3Sb
Fm-3m
Pmmn
a = 5.4977(3), b = 4.3301(1), c = 4.7698(2)
a = 6.0108(8)
a = 5.443(1), b = 4.3296(3), c = 4.711(1)
a = 19.2303(6), c = 4.3342(2)
a = 5.5054(5), b = 4.3409(2), c = 4.7631(5)
f = Cu10Sb3
P-3
a = 9.92390(6), c = 4.32223(5)
g = Cu2Sb
P4/nmm
a = 4.0018(2), c = 6.1031(5)
430 °C, 28 days
d = Cu78Sb20 P63/mmc
a = 19.156(1), c = 4.3273(4)
450 °C, 28 days
d = Cu78Sb20 P63/mmc
a = 19.022(5), c = 4.4541(9)
e = Cu3Sb
Pmmn
a = 5.3831(5), b = 4.2871(5), c = 5.0467(6)
g = Cu2Sb
470 °C, 28 days
600 °C, 28 days
P4/nmm
a = 4.2732(3), c = 5.7367(7)
d = Cu78Sb20 P63/mmc
a = 18.973(4), c = 4.4484(8)
e = Cu3Sb
Pmmn
a = 5.3763(7), b = 4.2818(5), c = 5.0382(5)
g = Cu2Sb
P4/nmm
a = 4.2675(2), c = 5.7335(7)
d = Cu78Sb20 P63/mmc
a = 18.992(4), c = 4.4519(8)
e = Cu3Sb
Pmmn
a = 5.3810(9), b = 4.2812(6), c = 5.0447(6)
g = Cu2Sb
P4/nmm
a = 4.2667(2), c = 5.7424(7)
d = Cu78Sb20 P63/mmc
g = Cu2Sb
P4/nmm
a = 4.00170(4), c = 6.1027(1)
280 °C, 28 days
f = Cu10Sb3
P-3
a = 9.92096(5), c = 4.32247(4)
400 °C, 28 days
170 °C, 6 months
280 °C, 28 days
340 °C, 28 days
400 °C, 28 days
Nonequilibrium (quenched
from liquid)
a = 5.49427(9), b = 4.34601(5), c = 4.75169(9)
170 °C, 6 months
340 °C, 28 days
b phase partially stabilized
a = 19.1990(2), c = 4.33742(8)
Pmmn
Pmmn
Nonequilibrium (quenched
from liquid)
a = 9.90817(7), c = 4.32364(5)
e = Cu3Sb
e = Cu3Sb
123
a = 9.89815(8), c = 4.32278(6)
a = 19.1655(1), c = 4.32620(3)
430 °C, 28 days
340 °C, 28 days
Cu74Sb26
a = 9.90716(7), c = 4.32301(8)
a = 19.1604(4), c = 4.3249(1)
340 °C, 28 days
e = Cu3Sb
Cu76Sb24
a = 4.0035(7), c = 6.087(2)
Pmmn
Cu77.5Sb22.5 Melt 1,000 °C, 1 day d = Cu78Sb20 P63/mmc
Nonequilibrium (not
sufficiently annealed)
a = 19.1476(2), c = 4.32586(9)
e = Cu3Sb
d = Cu78Sb20 P63/mmc
Comment
Nonequilibrium: b phase
decomposed during
quenching
Nonequilibrium: b phase
decomposed during
quenching
Nonequilibrium: b phase
decomposed during
quenching
a = 19.1412(1), c = 4.32539(6)
g = Cu2Sb
P4/nmm
a = 4.00200(4), c = 6.1038(1)
f = Cu10Sb3
P-3
a = 9.92319(6), c = 4.32294(4)
g = Cu2Sb
P4/nmm
a = 4.00364(5), c = 6.1042(2)
e = Cu3Sb
Pmmn
a = 5.5064(3), b = 4.35302(4), c = 4.7680(2)
a = (Cu)
Fm-3m
a = 3.6216(1)
d = Cu78Sb20 P63/mmc
a = 19.1335(5), c = 4.3248(1)
a = 9.9149(3), c = 4.3213(2)
f = Cu10Sb3
P-3
g = Cu2Sb
P4/nmm
a = 4.00201(3), c = 6.10281(9)
f = Cu10Sb3
P-3
a = 9.91867(6), c = 4.32272(4)
g = Cu2Sb
P4/nmm
a = 4.00203(2), c = 6.10400(8)
a = 9.91806(9), c = 4.32282(7)
f = Cu10Sb3
P-3
g = Cu2Sb
P4/nmm
a = 4.00295(4), c = 6.1034(1)
e = Cu3Sb
Pmmn
a = 5.5090(1), b = 4.35420(5), c = 4.7757(1)
g = Cu2Sb
P4/nmm
a = 4.00147(8), c = 6.1038(2)
Nonequilibrium (not
sufficiently annealed)
A new experimental phase diagram investigation of Cu–Sb
1281
Table 5 continued
Sample
Heat treatment
Cu72Sb28
Melt 1,000 °C, 1 day e = Cu3Sb
340 °C, 28 days
430 °C, 28 days
600 °C, 28 days
Cu70Sb30
430 °C, 28 days
470 °C, 28 days
Nonequilibrium (quenched
from liquid)
Pmmn
a = 5.5132(2), b = 4.35595(8), c = 4.7800(1)
g = Cu2Sb
P4/nmm
a = 4.00218(5), c = 6.1043(1)
a = 9.9206(1), c = 4.3219(1)
f = Cu10Sb3
P-3
g = Cu2Sb
P4/nmm
a = 4.00138(3), c = 6.1032(1)
e = Cu3Sb
Pmmn
a = 5.5197(2), b = 4.36081(9), c = 4.7898(2)
g = Cu2Sb
P4/nmm
a = 4.00352(4), c = 6.1059(1)
b = Cu3Sb
Fm-3m
a = 5.9979(9)
e = Cu3Sb
Pmmn
a = 5.3919(8), b = 4.2688(7), c = 5.0588(7)
g = Cu2Sb
P4/nmm
a = 4.00016(7), c = 6.0977(2)
e = Cu3Sb
Pmmn
a = 5.5157(2), b = 4.35768(8), c = 4.7830(1)
g = Cu2Sb
P4/nmm
a = 4.00130(3), c = 6.10265(8)
b = Cu3Sb
Fm-3m
a = 6.0384(9)
e = Cu3Sb
Pmmn
a = 5.5113(5), b = 4.3558(2), c = 4.7796(4)
P4/nmm
a = 4.00302(2), c = 6.10545(7)
a = 6.035(3)
e = Cu3Sb
Pmmn
a = 5.5039(3), b = 4.3540(1), c = 4.7787(2)
g = Cu2Sb
P4/nmm
a = 4.00170(3), c = 6.10306(8)
g = Cu2Sb
P4/nmm
a = 4.00231(2), c = 6.10442(8)
h = (Sb)
R-3m
a = 4.3060(1), c = 11.2701(7)
340 °C, 28 days
g = Cu2Sb
P4/nmm
a = 4.00172(3), c = 6.10443(9)
h = (Sb)
R-3m
a = 4.3066(1), c = 11.2689(6)
470 °C, 28 days
g = Cu2Sb
P4/nmm
a = 4.00204(2), c = 6.10431(7)
h = (Sb)
R-3m
a = 4.30686(9), c = 11.2708(5)
Melt 1000 °C, 1 day
340 °C, 28 days
340 °C, 28 days
535 °C, 28 days
Cu25Sb75
Comment
Fm-3m
535 °C, 28 days
Cu30Sb70
Lattice parameter /Å
b = Cu3Sb
600 °C, 28 days
Cu35Sb65
Structure
type
g = Cu2Sb
600 °C, 28 days
Cu60Sb40
Phase
340 °C, 28 days
535 °C, 28 days
g = Cu2Sb
P4/nmm
a = 4.00239(2), c = 6.10462(8)
h = (Sb)
R-3m
a = 4.3072(1), c = 11.2720(5)
g = Cu2Sb
P4/nmm
a = 4.00106(5), c = 6.1026(1)
h = (Sb)
R-3m
a = 4.30569(6), c = 11.2658(3)
g = Cu2Sb
P4/nmm
a = 4.00165(5), c = 6.1029(1)
h = (Sb)
R-3m
a = 4.30639(4), c = 11.2707(2)
g = Cu2Sb
P4/nmm
a = 4.00218(4), c = 6.1043(1)
h = (Sb)
R-3m
a = 4.30709(5), c = 11.2701(2)
g = Cu2Sb
P4/nmm
a = 4.00065(7), c = 6.1018(2)
h = (Sb)
R-3m
a = 4.30563(4), c = 11.2650(2)
g = Cu2Sb
P4/nmm
a = 4.00206(5), c = 6.1040(1)
h = (Sb)
R-3m
a = 4.30703(4), c = 11.2702(2)
g = Cu2Sb
P4/nmm
a = 4.00151(7), c = 6.1029(2)
h = (Sb)
R-3m
a = 4.30667(7), c = 11.2690(2)
To investigate the solubility ranges of the phases, we
performed SEM/EDX measurements on polished samples.
We were especially interested in determining the ranges of
homogeneity of the phases that had been only tentatively
fixed in the literature ([3], dashed lines). All of the results
of the EDX measurements along with BSE images of the
examined samples can be found in Table 7. Overall, the
ranges of homogeneity were found to fit well to the currently accepted phase diagram in the literature [3]. The
b phase partially stabilized
b phase partially stabilized
b phase partially stabilized
Nonequilibrium (quenched
from liquid)
Nonequilibrium (quenched
from liquid)
Nonequilibrium (quenched
from liquid)
Nonequilibrium (quenched
from liquid)
Nonequilibrium (quenched
from liquid)
solubility limits indicated by the dashed lines for the e
phase, g phase, and the high-temperature region of the d
phase were determined. For the e phase, an extension of the
phase field to higher Sb concentrations than those estimated in the literature [3] was observed, and the g phase
was also found to occur at higher Sb concentrations (see
Tables 7, 8; Fig. 4). Even the very narrow two-phase field
between the d and the f phases was confirmed by EDX and XRD
measurements of the sample with 20.5 at% Sb (see Table 5).
123
1282
S. Fürtauer, H. Flandorfer
Table 6 Detected phases in quenched samples
Sample
Annealing temperature (°C)
Melt
Cu90Sb10
170
280 340
(Cu) d
(Cu) d
Cu82.5Sb17.5 d, e
(Cu) d
Cu80.5Sb19.5
d
d, f, g
Cu79.5Sb20.5
Cu79Sb21
d, e
Cu77.5Sb22.5 d, e
Cu72Sb28
d, f
e, g
400 430
(Cu) d
435
450
480
535
600
(Cu) c, d
c, d
(Cu) b, d
d, f d, e
d, e
b, d, e
f, g
d, e
d, e, g d, e, g
d, e, g
e
e, g
f, g
e, g
e, g
g, (Sb)
470
(Cu) d (Cu) d (Cu) d (Cu) b, c (Cu) b, c
Cu, d
Cu70Sb30
Cu60Sb40
420
f
d, g
f, g f, g
(Cu) d, f, g f, g f, g
Cu76Sb24
Cu74Sb26
350 420 390
g, (Sb)
b, e, g
b, e, g
b, e, g
g, (Sb)
g, (Sb)
Cu35Sb65
g, (Sb)
g, (Sb)
Cu30Sb70
g, (Sb)
g, (Sb)
Cu25Sb75
g, (Sb)
g, (Sb)
Bold-underlined quenched from liquid, bold insufficiently annealed, italic-underlined decomposition of b phase
Fig. 3 XRD patterns of quenched Cu90Sb10 and Cu82.5Sb17.5 samples annealed at different temperatures
Experimental
Sample preparation
Samples with 10–75 at% Sb (see Table 9) were prepared from 99.98% Cu (Goodfellow, Cambridge, UK;
treated under an H2 flow at 200 °C for 5 h to remove
oxide layers) and 99.999% Sb (Alfa Aesar, Karlsruhe,
Germany; the surface oxide layer was removed by
filtration of the melt through quartz glass wool).
Weighed amounts of the metals were sealed in quartz
glass ampoules under vacuum (*10-3 mbar) and
123
alloyed in a resistance furnace at 1,000 °C for a few
hours. Annealing was performed again in evacuated
quartz glass ampoules for 28 days at selected temperatures (170–600 °C, annealing time at 170 °C was
6 months). Finally, the alloys were quenched in cold
water.
Analytical methods
Experimental techniques applied were powder X-ray
diffraction (XRD), thermal analysis (DTA), and metallographic methods (EPMA/ESEM). Thermal analysis was
A new experimental phase diagram investigation of Cu–Sb
1283
done with a TG/DTA Setsys Evolution instrument from
Setaram. The measurements were performed in open
alumina crucibles under an Ar atmosphere; slices of Ti
sheet in the second crucible were used as reference
material.
The powder XRD measurements were done on a Bruker
D8 diffractometer (h/2h geometry) at ambient temperature.
X-rays were produced in a copper radiation source at an
accelerating voltage of 40 kV and with an electron current
of 40 mA. A Ni filter was used to remove the Kb radiation.
Table 7 ESEM/EPMA results of Cu–Sb phase compositions
Sample
Cu90Sb10
Cu82.5Sb17.5
Ann. temp. /°C
Phase 1 (dark)
Phase 2 (bright)
at% Cu
at% Sb
SEM image
at% Cu
at% Sb
600
(Cu)
93.0
7.0
bCu
80.2
19.8
450
(Cu)
93.9
6.1
cCu
82.3
17.7
340
(Cu)
96.0
4.0
dCu
78.8
21.2
600
(Cu)
93.7
7.0
dCu
81.0
19.0
470
cSb
81.7
18.3
dCu
80.0
20.0
123
1284
S. Fürtauer, H. Flandorfer
Table 7 continued
Sample
Ann. temp. /°C
Phase 1 (dark)
Phase 2 (bright)
at% Cu
at% Sb
SEM image
at% Cu
at% Sb
Cu79.5Sb20.5
350
fCu
77.2
22.8
dSb
78.0
22.0
Cu79Sb21
470
dSb
79.5
20.5
eCu
76.2
23.8
Cu77.5Sb22.5
430
dSb
79.6
20.4
eCu
76.7
23.4
Cu76Sb24
170
dSb (? small crystals of g)
77.5
22.5
gCu
66
34.0
Cu74Sb26
400
eSb
74.4
25.6
gCu
65.2
34.8
123
A new experimental phase diagram investigation of Cu–Sb
1285
Table 7 continued
Sample
Cu72Sb28
Cu60Sb40
Ann. temp. /°C
Phase 1 (dark)
Phase 2 (bright)
at% Cu
at% Sb
SEM image
at% Cu
at% Sb
430
eSb
73.7
26.3
gCu
64.7
35.3
340
fSb
78.0
22.0
gCu
65.5
34.5
470
gSb
64
36
(Sb)
0.1
99.9
Table 8 Comparison of temperature-invariant reactions in the Cu–Sb system in this work and in [1]
Reaction
Composition /at% Sb
L!b
29.0 (29.0)
Temp. /°C
Reaction type
690 (683)
Congruent melt
L ! ðCuÞ þ b
7.8 (5.8)
17.7 (19)
20.4 (19.5)
645 (645)
Eutectic
Lþb!g
31.0b
35.5 (33.5)
46.0b
586 (586)
Peritectic
b
L ! g þ ðSbÞ
35.5 (33.5)
63.0
99.9 (99.9)
526 (526)
Eutectic
ðCuÞ þ b ! c
6.4 (5.65)
16.5 (15.5)
20.7 (21.5)
484 (488)
Peritectoid
bþc!d
17.5 (16.5)
19.5 (19.0)
21.5 (24.0)
467 (462)
Peritectoid
bþd!e
20.2 (19.5)
22.3 (23.0)
23.9 (25.5)
440 (445a)
Peritectoid
b! eþg
26.3 (25.5)
29.3 (26.5)
34.2 (32.0)
427 (440a)
Eutectoid
c ! ðCuÞ þ d
5.0 (4.6)
16.5 (15.5)
19.0 (18.5)
440 (400)
Eutectoid
dþe!f
20.2 (20.0)
20.8 (21.5)
23.2 (23.5)
390a,b
Peritectoid
e!fþg
f!dþg
22.2 (22.5)
20.2 (20.0)
24.0 (24.0)
20.8 (21.5)
34.4 (32.5)
34.4 (32.5)
360 (360)
260 (260a)
Eutectoid
Eutectoid
Values in parentheses are from the literature [1]
a
Uncertain values
b
Value from [1]
123
1286
S. Fürtauer, H. Flandorfer
Fig. 4 New version of the Cu–Sb phase diagram
Table 9 Annealing temperatures
Sample
Annealing temperature /°C
Cu90Sb10
Melt
340
Cu82.5Sb17.5
Melt
340
Cu80.5Sb19.5
Melt
340
Cu79.5Sb20.5
Melt
170
280
390
435
420
450
430
350
470
480
600
470
600
420
Cu79Sb21
Melt
340
430
Cu77.5Sb22.5
Melt
340
430
Cu76Sb24
Melt
170
280
340
400
Cu74Sb26
Melt
170
280
340
400
Cu72Sb28
Melt
Cu70Sb30
Melt
Cu60Sb40
Cu35Sb65
Melt
Melt
340
340
Cu30Sb70
Melt
340
535
Cu25Sb75
Melt
340
535
340
470
450
470
600
430
430
600
470
600
470
600
535
Underlined only XRD, bold XRD/ESEM, italics XRD/ESEM/DTA
The powder was fixed with petroleum jelly on a silicon
monocrystal sample carrier, which was rotated during the
measurement. The detection unit was the Lynxeye strip
detector. Rietveld refinement of the data was done with the
Topas3Ò software provided by Bruker AXS.
An optical microscope (Zeiss Axiotech 100 reflected
light microscope) as well as EDX techniques (energy-
123
dispersive spectroscopy; ESEM Zeiss Supra 55 VP) were
used for metallographic investigations. In the ESEM, the
excitation energy of the electron beam was 15–20 kV.
Backscattered electrons were detected in order to visualize the surfaces of our samples. The characteristic
spectral lines were used for EDX: the Cu K line and the
Sb L line.
A new experimental phase diagram investigation of Cu–Sb
Acknowledgments We wish to thank the FWF (Fonds zur Förderung der wissenschaftlichen Forschung), who provided the funds for
this work through the project P21507-N19. Many thanks also to Dr.
Stephan Puchegger from the Center for Nano Structure Research,
University of Vienna, for supporting our SEM/EDX measurements.
Open Access This article is distributed under the terms of the
Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original
author(s) and the source are credited.
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