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Experimental investigation and thermodynamic prediction of the Ni–Pb–Sb phase diagram
CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 35 (2011) 308–313
Contents lists available at SciVerse ScienceDirect
CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry journal homepage: www.elsevier.com/locate/calphad
Experimental investigation and thermodynamic prediction of the Ni–Pb–Sb phase diagram Duško Minić a,∗ , Dragan Manasijević b , Vladan Ćosovic c , Andreja Todorović a , Irma Dervišević a , Dragana Živković b , Jelena Ðokić a a
University of Pristina, Faculty of Technical Sciences, 38220 Kosovska Mitrovica, Serbia
b
University of Belgrade, Technical Faculty, VJ 12, 19210 Bor, Serbia
c
Institute of Chemistry, Technology and Metallurgy, Njegoševa 12, 11000 Belgrade, Serbia
article
info
Article history: Received 6 December 2010 Received in revised form 13 April 2011 Accepted 14 April 2011 Available online 8 May 2011 Keywords: Ni–Pb–Sb ternary system Phase diagram Thermal analysis Thermodynamic prediction
abstract The phase diagram of the ternary Ni–Pb–Sb system was investigated experimentally by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS) methods, and predicted using the calculation of phase diagrams (CALPHAD) method. The phase transition temperatures of alloys along three predicted vertical sections of the Ni–Pb–Sb ternary system, with molar ratio Ni : Sb = 1 : 3, Ni : Pb = 1, and x(Sb) = 0.6, were measured by DSC. The predicted isothermal section at 700 °C was compared with the results of the SEM–EDS analysis in this work. © 2011 Elsevier Ltd. All rights reserved.
1. Introduction Nickel is a heavy non-ferrous metal, with outstanding resistance to corrosion and good water resistance, and it is magnetic up to 360 °C, with good thermal conductivity. Nickel is used for the production of numerous alloys used in different industries. Also, low melting temperature alloys from the Pb–Sb system and the Al–Ni–Sb system have many industrial applications, especially in sliding bearing production. This wide industrial application of Ni and Ni–Sb based alloys in general as well as the limited literature data regarding the ternary Ni–Pb–Sb system initiated this study. The binary Ni–Sb system has recently been investigated by many authors. Naud and Parijs [1] determined some phases in the Ni–Sb system in which the solid solubility of antimony in nickel increased to 9.4 at.% Sb. Wodniecki and Uhrmacher [2] studied Ni–Sb intermetallic compounds with different stoichiometries by using perturbed angular correlation (PAC) spectroscopy. The hyperfine interaction parameters in the crystal lattices of NiSb, Ni5 Sb2 , Ni3 Sb, and NiSb2 were determined. Randl et al. [3] studied the structure of the intermetallic alloy Ni3 Sb (the high-temperature phase) at temperatures ranging from 600 to 100 °C by using a neutron
∗
Corresponding author. Tel.: +381 63 7025683. E-mail address: [email protected] (D. Minić).
0364-5916/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.calphad.2011.04.003
diffraction method. Popovic et al. [4] reported the thermodynamic activities of antimony for Ni–Sb alloys in the composition range between 20 and 52 at.% of Sb by using the Knudsen effusion mass spectrometry (KEMS) method. Cao et al. [4,5] made a thermodynamic assessment of the Ni–Sb binary alloy system by using the CALPHAD method [6,7]. In this study, the phase transition temperatures of the Ni–Pb–Sb ternary system were investigated using differential scanning calorimetry (DSC). The phase compositions of selected equilibrated samples were determined experimentally using scanning electron microscopy with energy dispersive spectrometry (SEM–EDS) and compared with predicted phase equilibria at 700 °C. 2. Experimental procedure The samples, with a total mass of about 2 g, were prepared by high-frequency induction melting of pure metals (purity higher than 99.99%) in an argon atmosphere. The samples for SEM–EDS were equilibrated at 700 °C in an evacuated sealed quartz tube for one month and quenched in ice water. The phase transformation temperatures were determined by the DSC method. The DSC measurements were performed on an SDT Q600 (TA instruments). Alumina crucibles were used and measurements were performed under flowing argon atmosphere. The sample masses were about 30 mg. A heating rate of 5 °C/min
D. Minić et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 35 (2011) 308–313
309
Fig. 1. Calculated phase diagrams of the binary systems: (a) Ni–Sb; (b) Ni–Pb, and (c) Pb–Sb.
was used both for calibration and measurement of the prepared samples. Scanning electron microscopy (SEM: JEOL JSM 6460) with energy dispersive spectrometry (EDS: Oxford Instruments) was used for microstructure investigation and for phase composition determination. 3. Thermodynamic models and crystallographic data The phase diagram of the Ni–Pb–Sb system was calculated using only published thermodynamic descriptions for the constitutive binary systems. The Gibbs free energy functions for pure elements are taken from the SGTE database [8]. The thermodynamic parameters for the Ni–Pb, Ni–Sb, and Pb–Sb systems are taken from the papers of Wang et al. [9], Zhang et al. [10], and Ohtani and Ishida [11], respectively. There are eight binary phases in the ternary Ni–Pb–Sb system. Their common names,
Table 1 Phases considered and their crystal structures [10,12]. Common name of phase
Thermodynamic database name
Pearson’s symbol
Liquid (Ni), (Pb) (Sb)
LIQUID FCC_A1 RHOMBO_A7 NI3SB_BETA NISB_GAMMA NI3SB_DELTA NI5SB2 NISB2
– cF 4 hR2 cF 16 hP4 oP8 mC 28 oP6
β γ δ θ ζ
thermodynamic database names, and crystallographic data are given in Table 1. The LIQUID, FCC_A1, and RHOMBO_A7 solution phases are modeled using a random substitutional model. The compound phases from the Ni–Sb binary system are treated with the
310
D. Minić et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 35 (2011) 308–313
Table 2 The optimized binary parameters used in this study [9–11]. Phase and thermodynamic model
LIQUID (Ni, Pb, Sb)
FCC_A1 (Ni, Pb, Sb)1 (Va)1
RHOMBO_A7 (Pb, Sb)1
NI3SB_BETA (Sb)0.25 (Ni%, Va)0.5 (Va%, Ni)0.25
Thermodynamic parameters
= 31532.257 − 2.425T
[9]
1 LIQUID LNi,Pb
= 10459.949 − 2.498T
[9]
2 LIQUID LNi,Pb
= −10927.180 + 7.952T
[9]
3 LIQUID LNi,Pb
= −3732.467 − 0.109T
[9]
0 LIQUID LNi,Sb
= −73580.86 − 4.01441T
[10]
1 LIQUID LNi,Sb
= −12843.3 − 11.0286T
[10]
2 LIQUID LNi,Sb
= −4010 + 9.7T
[10]
0 LIQUID LPb,Sb
= 110 − 2.5T
[11]
1 LIQUID LPb,Sb
= −420 + 1.05T
[11]
2 LIQUID LPb,Sb
= 0.36T
[11]
0 FCC_A1 LNi,Pb:Va
= 29980 + 0.59T
[9]
1 FCC_A1 LNi,Pb:Va
= −20000 + 25T
[9]
0 FCC_A1 LNi,Sb:Va
= −64860 + 17.119T
[10]
1 FCC_A1 LNi,Sb:Va
= −33663.84 + 4.5T
[10]
2 FCC_A1 LNi,Sb:Va
= −38039.58 + 3.034T
[10]
0 FCC_A1 LPb,Sb:Va
= 11400 − 22.66T
[11]
0 RHOMBO_A7 LPb,Sb
= 21360 − 5.66T
GNI3SB_BETA = −19150 − 3.3T + 0.75 GHSERNI + 0.25 GHSERSB Sb:Ni:Ni
[10]
0
GNI3SB_BETA = −17522.75 − 1.74087 + 0.5 GHSERNI + 0.25 GHSERSB Sb:Ni:Va
[10]
0
GNI3SB_BETA = −6235.57 + 8.93666358T + 0.25 GHSERNI + 0.25 GHSERSB Sb:Va:Ni
[10]
0
GNI3SB_BETA = 5312 + 19.5T + 0.25 GHSERSB Sb:Va:Va
[10]
0 NI3SB_BETA LSb:Ni,Va:Va
= 2000 − 9.88685T
[10]
0 NI3SB_BETA LSb:Ni,Va:Ni
= 2000 − 9.88685T
[10]
0 NI3SB_BETA LSb:Ni:Ni,Va
= −7508.25 + 8.78T
[10]
0 NI3SB_BETA LSb:Va:Ni,Va
= −7508.25 + 8.78T
= −23310 + 19.82T − 3.50035T ln T + 0.00932581948T − 3.009 × 10 T + 0.333GHSERNI + 0.333 GHSERSBLOW
T + 7.414 ×
−6 3
[10]
GNISB_GAMMA = −16000 + 2T + 0.6667 GHSERNI + 0.3333 GHSERSB Sb:Ni:Ni
[10]
0
GNISB_GAMMA = 5522.55 + 1.3T + 0.3333 GHSERSB Sb:Va:Va
[10]
0
GNISB_GAMMA = −3182.1533 + 52.79T + 0.333 GHSERNI + 0.333 GHSERSB Sb:Va:Ni
[10]
= −1200 − 2T
[10]
0 NISB_GAMMA LSb:Ni,Va:Ni
= −1200 − 2T
[10]
0 NISB_GAMMA LSb:Ni:Ni,Va
= −13500 + 3T
[10]
0 NISB_GAMMA LSb:Va:Ni,Va
= −13500 + 3T
[10]
0
GNISB_DELTA = 3500 − 1.11 + GHSERNI Ni:Ni
0
GNISB_DELTA = −21460 − 1.31T + 0.75 GHSERNI + 0.25 GHSERSB Ni:Sb
[10]
0
GNISB_DELTA = −7252.56 + 11T Ni:Ni,Sb
[10]
0
GNI5SB2 = 2201.1 + 0.80005T + GHSERNI Ni:Ni
[10]
0
GNI5SB2 Ni:Sb = −23928.52 − 1.1T + 0.7143 GHSERNI + 0.2857 GHSERSB
0 NI5SB2 LNi:N,Sbi
NISB2 (Ni)0.3333 (Sb)0.6667
2
0
0 NISB_GAMMA LSb:Ni,Va:Va
NI5SB2 (Ni)0.7143 (Ni, Sb)0.2857
[10]
GNISB_GAMMA Sb:Ni:Va −21 7
10
NI3SB_DELTA (Ni)0.75 (Ni, Sb)0.25
[11]
0
0
NISB_GAMMA (Sb)0.3333 (Ni, Va)0.3333 (Va, Ni)0.3333
References
0 LIQUID LNi,Pb
0
[10]
= −7150 + 6T
GNISB2 Ni:Sb = −26020 + 4.43T + 0.3333 GHSERNI + 0.6667 GHSERSB
sublattice model [10]. The intermediate phases γ (NISB_GAMMA) and β (NI3SB_BETA), both with extensive homogeneity ranges, were described using three sublattices: (Sb) 1/3 (Ni%, Va) 1/3 (Va%, Ni) 1/3 and (Sb) 1/4 (Ni%, Va) 1/2 (Ni%, Va) 1/4. The two low-temperature phases δ (NI3SB_DELTA) and θ (NI5SB2), with narrow homogeneity ranges, were modeled as two sublattices: (Ni) 3/4 (Sb, Ni) 1/4 and (Ni) 5/7 (Sb, Ni) 2/7. The intermetallic compound ξ (NiSb2), with no homogeneity range, was treated as a stoichiometric compound [10]. The binary thermodynamic parameters used for the prediction of phase equilibria in the Ni–Pb–Sb system are listed in Table 2.
[10] [10] [10]
The calculated binaries Ni–Sb, Ni–Pb, and Pb–Sb are presented in Fig. 1. The binary Pb–Sb system represents a eutectic system, as well as the binary Ni–Pb system, having a miscibility gap in the liquid state. The binary Ni–Sb system is a complex binary system, in which nickel and antimony form several intermetallic compounds, and numerous reactions occur. 4. Literature data The ternary Ni–Pb–Sb system was experimentally investigated by Zeng and Lin [13]. They proposed the isothermal section of
D. Minić et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 35 (2011) 308–313
311
Table 3 DSC results of the investigated alloys of the ternary Ni–Pb–Sb system. Alloy composition
Phase transition temperatures (°C) Liquidus temperature
Fig. 2. Isothermal section of the ternary Ni–Pb–Sb system at 500 K [13].
x(Pb)
x(Ni)/x(Sb) = 1/3
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
980 1020 1087 1078 1261 1103 1285 1251 1087
x(Sb)
x(Ni)/x(Pb) = 1
0.5 0.6 0.7 0.8 0.9
1135 1009 861 808 742
x(Pb)
x(Sb) = 0, 6
0.1 0.15 0.2 0.25 0.3
1076 1065 1041 1023 943
Other phase transition
252; 527 252; 507 253; 483 250; 329; 450 252; 421 258; 379 261; 1096 257; 1092 250; 297
252; 450 250; 512 251 248 249
249; 525 247; 521 253; 501 252; 464 251; 479
The intensive thermal effect close to the predicted temperature of the ternary eutectic reaction at 252.4 °C is observed for all investigated samples. The experimentally determined liquidus temperatures for several investigated samples differ considerably from the predicted values. 5.2. Microstructure investigation results
Fig. 3. DSC curve for the Ni15 Pb25 Sb60 alloy with determined phase transition temperatures.
the Ni–Pb–Sb ternary system at 500 K, constructed using Xray diffraction (XRD) and metallographic results. There were five three-phase regions, eleven two-phase regions, and seven singlephase regions in that section (Fig. 2), and the maximum solid solubility of Sb in Ni was about 6.25 at.% Sb. The maximum solid solubility of Sb in Pb was about 3.9 at.% Sb. The homogeneity range of NiSb extended from about 49 to 52.3 at.% Sb at 500 K. No ternary compounds were reported. 5. Results and discussion
The compositions of coexisting phases of three samples, equilibrated at 700 °C, were investigated using the SEM–EDS method. Their overall compositions and experimentally determined compositions of coexisting phases are given in Table 4. The maximum experimental error in determined phase compositions is within the range ±4 at.%. The calculated isothermal section of the ternary Ni–Pb–Sb system at 700 °C and experimentally determined phase composition for samples 1, 2 and 3 are presented in Fig. 5 for comparison. Three alloys were examined: two of them from the twophase region (LIQUID+NISB_GAMMA) and one from the threephase region (NISB_GAMMA+LIQUID+NI3SB_BETA). The calculated equilibria and experimental values obtained by SEM–EDS method show good agreement. The SEM microstructure of sample 3, with phases marked, is presented in Fig. 6.
5.1. Thermal analysis results
5.3. Predicted liquidus projection and invariant equilibria
In order to experimentally study the phase transition temperatures of the Ni–Pb–Sb ternary system and to make a comparison with the thermodynamic predictions, alloys along three chosen vertical sections with molar ratio x(Ni) : x(Sb) = 1 : 3, x(Ni) : x(Pb) = 1, and x(Sb) = 0.6, were investigated using DSC. The temperatures of invariant phase transitions were taken from the extrapolated peak onset on heating. The other phase transition temperatures were taken from the peak temperature. The overall DSC results from this work are given in Table 3. The DSC thermograph for the alloy Ni15 Pb25 Sb60 is presented in Fig. 3. The predicted vertical sections and experimentally obtained phase transition temperatures are shown in Fig. 4(a)–(c).
The extrapolated liquidus projection of the Ni–Pb–Sb ternary system is plotted in Fig. 7. The calculated liquidus projection shows a large composition region of liquid immiscibility. Two ternary monotectic reactions (E1 and E2), with the ternary monotectic points located close to the Ni–Sb boundary system, were predicted in this system. A ternary eutectic reaction (E3), with ternary eutectic point situated very close to the Pb–Sb binary eutectic point, was calculated to be at 252.4 °C. This temperature represents the lowest temperature of thermodynamic stability of the liquid phase in this ternary system according to the thermodynamic prediction. This eutectic reaction was experimentally confirmed by DSC results from this study (Table 3). However, the predicted Pb-rich part of the liquidus projection is very doubtful. It includes
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D. Minić et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 35 (2011) 308–313
Fig. 4. Calculated vertical sections of the Ni–Pb–Sb ternary system compared with DSC results from the present study: (a) x(Ni) : x(Sb) = 1 : 3, (b) x(Ni) : x(Pb) = 1, and (c) x(Sb) = 0.6.
Table 4 Calculated and experimentally determined phase compositions for the ternary Ni–Pb–Sb system at 700 °C. Overall composition (at.%)
Theoretic predicted phases
LIQUID NISB_GAMMA LIQUID NISB_GAMMA NI3SB_BETA LIQUID NISB_GAMMA
18.4 Pb 20.6 Ni 61 Sb 20 Pb 49 Ni 31 Sb 38 Pb 20.5 Ni 41.5 Sb
Experiment determined phases
LIQUID NISB_GAMMA LIQUID NISB_GAMMA NI3SB_BETA LIQUID NISB_GAMMA
Exp. compositions of phases (at.%) Ni
Pb
Sb
1.92 ± 0.92 45.53 ± 1.23 2.95 ± 2.47 53.53 ± 0.09 68.87 ± 1.96 1.13 ± 0.773 48 ± 0.61
33.77 ± 0.97 1.34 ± 1.06 95.27 ± 3.99 0.69 ± 0.69 1.36 ± 1.36 65.93 ± 1.01 0,65 ± 0.22
64.31 ± 0.04 53.13 ± 0.17 1.78 ± 1.53 45.78 ± 0.78 29.77 ± 0.6 32.46 ± 0.24 51.35 ± 0.38
Table 5 Predicted invariant reactions in the Ni–Pb–Sb ternary system (outside the Pb-rich composition region). Type
T (°C)
Reaction
E1 E2 E3
1079.2 1060.1 252.4
LIQUID → LIQUID + NI3SB_BETA + FCC_A1 LIQUID → LIQUID + NI3SB_BETA + NISB_GAMMA NISB_GAMMA + RHOMBO_A7 + FCC_A1 → LIQUID
a
The composition of LIQUID is very close to that of the boundary of the Pb–Sb system.
Composition (at.%) Ni
Pb
79.4 60.9 0a
3.1 3.3 82.2
D. Minić et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 35 (2011) 308–313
Fig. 5. Predicted isothermal section of the ternary Ni–Pb–Sb system at 700 °C and experimental values of the phase compositions for the samples 1, 2, and 3.
313
Fig. 7. Predicted liquidus projection of the ternary Ni–Pb–Sb system.
has been conducted using DSC and SEM–EDS. The experimental results were compared with the results of thermodynamic binarybased prediction. The calculated isothermal section at 700 °C shows reasonable agreement with the results of the SEM–EDS analysis. The melting behavior of the different Ni–Pb–Sb alloys has been determined. A ternary eutectic at 252.4 °C was experimentally verified. The experimental results reported in this study can be used for further thermodynamic assessment of phase equilibria in the Ni–Pb–Sb ternary system. Acknowledgments This work was supported by the Ministry of Science of the Republic of Serbia (Project No. OI172037). Appendix. Supplementary data Fig. 6. SEM microstructure of alloy 3.
the primary crystallization fields of the binary intermetallic phases from the boundary Ni–Sb binary system (NI3SB_BETA and NISB_GAMMA) and very small fields (NISB_DELTA, NI5SB2, and NISB2), visible only under magnification, all located very close to pure Pb. These predicted primary crystalline phases and related predicted ternary invariant reactions were not verified experimentally in the present study, and are not indicated in Fig. 7 and in Table 5. 6. Conclusion The phase equilibria in the Ni–Pb–Sb ternary system were extrapolated using optimized binary thermodynamic parameters. The predicted phase diagram shows a large composition region of liquid immiscibility and the existence of three E-type reactions. The predicted phase equilibria in the Pb-rich corner (very close to pure Pb) of the ternary diagram are doubtful, and are not in agreement with the binary phase equilibria, which indicates that the ternary interactions are significant. A preliminary experimental investigation of Ni–Pb–Sb ternary phase diagram
Supplementary material related to this article can be found online at doi:10.1016/j.calphad.2011.04.003. References [1] J. Naud, D. Parijs, Mater. Res. Bull. 7 (4) (1972) 301. [2] P. Wodniecki, M. Uhrmacher, Appl. Phys. A: Mater. Sci. Process. 57 (5) (1993) 469. [3] O.G. Randl, G. Vogl, M. Kaisermayr, W. Bührer, J. Pannetier, W. Petry, J. Phys.: Condens. Matter 8 (41) (1996) 7689. [4] A. Popovic, O. Semenova, K.W. Richter, R. Krachler, G. Bester, H. Ipser, Intermetallics 15 (7) (2007) 862. [5] Z. Cao, Y. Takaku, I. Ohnuma, R. Kainuma, H. Zhu, K. Ishida, Rare Metals 27 (4) (2008) 384. [6] N. Saunders, A.P. Miodownik, CALPHAD (A Comprehensive Guide), Elsevier, London, 1998. [7] H.L. Lukas, S.G. Fries, B. Sundman, Computational Thermodynamics: CALPHAD Method, Cambridge University Press, Cambridge, UK, 2007. [8] A.T. Dinsdale, SGTE unary database, Version 4.4, 2002. www.sgte.org. [9] Y. Zhang, L. Changrong, D. Zhenmin, G. Cuiping, CALPHAD 32 (2008) 378. [10] C.P. Wang, X.J. Liu, I. Ohnuma, R. Kainuma, K. Ihida, CALPHAD 24 (2) (2000) 149. [11] H. Ohtani, K. Ishida, J. Phase Equilib. 16 (5) (1995) 416. [12] A.T. Dinsdale, A. Kroupa, J. Vizdal, J. Vrestal, A. Watson, A. Zemanova, COST action 531–atlas of lead free soldering, Volume 1, COST Office, Brussels, Belgium, 2008. [13] L. Zeng, G. Lin, J. Alloys Compd. 395 (2005) 101.
Contents lists available at SciVerse ScienceDirect
CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry journal homepage: www.elsevier.com/locate/calphad
Experimental investigation and thermodynamic prediction of the Ni–Pb–Sb phase diagram Duško Minić a,∗ , Dragan Manasijević b , Vladan Ćosovic c , Andreja Todorović a , Irma Dervišević a , Dragana Živković b , Jelena Ðokić a a
University of Pristina, Faculty of Technical Sciences, 38220 Kosovska Mitrovica, Serbia
b
University of Belgrade, Technical Faculty, VJ 12, 19210 Bor, Serbia
c
Institute of Chemistry, Technology and Metallurgy, Njegoševa 12, 11000 Belgrade, Serbia
article
info
Article history: Received 6 December 2010 Received in revised form 13 April 2011 Accepted 14 April 2011 Available online 8 May 2011 Keywords: Ni–Pb–Sb ternary system Phase diagram Thermal analysis Thermodynamic prediction
abstract The phase diagram of the ternary Ni–Pb–Sb system was investigated experimentally by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS) methods, and predicted using the calculation of phase diagrams (CALPHAD) method. The phase transition temperatures of alloys along three predicted vertical sections of the Ni–Pb–Sb ternary system, with molar ratio Ni : Sb = 1 : 3, Ni : Pb = 1, and x(Sb) = 0.6, were measured by DSC. The predicted isothermal section at 700 °C was compared with the results of the SEM–EDS analysis in this work. © 2011 Elsevier Ltd. All rights reserved.
1. Introduction Nickel is a heavy non-ferrous metal, with outstanding resistance to corrosion and good water resistance, and it is magnetic up to 360 °C, with good thermal conductivity. Nickel is used for the production of numerous alloys used in different industries. Also, low melting temperature alloys from the Pb–Sb system and the Al–Ni–Sb system have many industrial applications, especially in sliding bearing production. This wide industrial application of Ni and Ni–Sb based alloys in general as well as the limited literature data regarding the ternary Ni–Pb–Sb system initiated this study. The binary Ni–Sb system has recently been investigated by many authors. Naud and Parijs [1] determined some phases in the Ni–Sb system in which the solid solubility of antimony in nickel increased to 9.4 at.% Sb. Wodniecki and Uhrmacher [2] studied Ni–Sb intermetallic compounds with different stoichiometries by using perturbed angular correlation (PAC) spectroscopy. The hyperfine interaction parameters in the crystal lattices of NiSb, Ni5 Sb2 , Ni3 Sb, and NiSb2 were determined. Randl et al. [3] studied the structure of the intermetallic alloy Ni3 Sb (the high-temperature phase) at temperatures ranging from 600 to 100 °C by using a neutron
∗
Corresponding author. Tel.: +381 63 7025683. E-mail address: [email protected] (D. Minić).
0364-5916/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.calphad.2011.04.003
diffraction method. Popovic et al. [4] reported the thermodynamic activities of antimony for Ni–Sb alloys in the composition range between 20 and 52 at.% of Sb by using the Knudsen effusion mass spectrometry (KEMS) method. Cao et al. [4,5] made a thermodynamic assessment of the Ni–Sb binary alloy system by using the CALPHAD method [6,7]. In this study, the phase transition temperatures of the Ni–Pb–Sb ternary system were investigated using differential scanning calorimetry (DSC). The phase compositions of selected equilibrated samples were determined experimentally using scanning electron microscopy with energy dispersive spectrometry (SEM–EDS) and compared with predicted phase equilibria at 700 °C. 2. Experimental procedure The samples, with a total mass of about 2 g, were prepared by high-frequency induction melting of pure metals (purity higher than 99.99%) in an argon atmosphere. The samples for SEM–EDS were equilibrated at 700 °C in an evacuated sealed quartz tube for one month and quenched in ice water. The phase transformation temperatures were determined by the DSC method. The DSC measurements were performed on an SDT Q600 (TA instruments). Alumina crucibles were used and measurements were performed under flowing argon atmosphere. The sample masses were about 30 mg. A heating rate of 5 °C/min
D. Minić et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 35 (2011) 308–313
309
Fig. 1. Calculated phase diagrams of the binary systems: (a) Ni–Sb; (b) Ni–Pb, and (c) Pb–Sb.
was used both for calibration and measurement of the prepared samples. Scanning electron microscopy (SEM: JEOL JSM 6460) with energy dispersive spectrometry (EDS: Oxford Instruments) was used for microstructure investigation and for phase composition determination. 3. Thermodynamic models and crystallographic data The phase diagram of the Ni–Pb–Sb system was calculated using only published thermodynamic descriptions for the constitutive binary systems. The Gibbs free energy functions for pure elements are taken from the SGTE database [8]. The thermodynamic parameters for the Ni–Pb, Ni–Sb, and Pb–Sb systems are taken from the papers of Wang et al. [9], Zhang et al. [10], and Ohtani and Ishida [11], respectively. There are eight binary phases in the ternary Ni–Pb–Sb system. Their common names,
Table 1 Phases considered and their crystal structures [10,12]. Common name of phase
Thermodynamic database name
Pearson’s symbol
Liquid (Ni), (Pb) (Sb)
LIQUID FCC_A1 RHOMBO_A7 NI3SB_BETA NISB_GAMMA NI3SB_DELTA NI5SB2 NISB2
– cF 4 hR2 cF 16 hP4 oP8 mC 28 oP6
β γ δ θ ζ
thermodynamic database names, and crystallographic data are given in Table 1. The LIQUID, FCC_A1, and RHOMBO_A7 solution phases are modeled using a random substitutional model. The compound phases from the Ni–Sb binary system are treated with the
310
D. Minić et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 35 (2011) 308–313
Table 2 The optimized binary parameters used in this study [9–11]. Phase and thermodynamic model
LIQUID (Ni, Pb, Sb)
FCC_A1 (Ni, Pb, Sb)1 (Va)1
RHOMBO_A7 (Pb, Sb)1
NI3SB_BETA (Sb)0.25 (Ni%, Va)0.5 (Va%, Ni)0.25
Thermodynamic parameters
= 31532.257 − 2.425T
[9]
1 LIQUID LNi,Pb
= 10459.949 − 2.498T
[9]
2 LIQUID LNi,Pb
= −10927.180 + 7.952T
[9]
3 LIQUID LNi,Pb
= −3732.467 − 0.109T
[9]
0 LIQUID LNi,Sb
= −73580.86 − 4.01441T
[10]
1 LIQUID LNi,Sb
= −12843.3 − 11.0286T
[10]
2 LIQUID LNi,Sb
= −4010 + 9.7T
[10]
0 LIQUID LPb,Sb
= 110 − 2.5T
[11]
1 LIQUID LPb,Sb
= −420 + 1.05T
[11]
2 LIQUID LPb,Sb
= 0.36T
[11]
0 FCC_A1 LNi,Pb:Va
= 29980 + 0.59T
[9]
1 FCC_A1 LNi,Pb:Va
= −20000 + 25T
[9]
0 FCC_A1 LNi,Sb:Va
= −64860 + 17.119T
[10]
1 FCC_A1 LNi,Sb:Va
= −33663.84 + 4.5T
[10]
2 FCC_A1 LNi,Sb:Va
= −38039.58 + 3.034T
[10]
0 FCC_A1 LPb,Sb:Va
= 11400 − 22.66T
[11]
0 RHOMBO_A7 LPb,Sb
= 21360 − 5.66T
GNI3SB_BETA = −19150 − 3.3T + 0.75 GHSERNI + 0.25 GHSERSB Sb:Ni:Ni
[10]
0
GNI3SB_BETA = −17522.75 − 1.74087 + 0.5 GHSERNI + 0.25 GHSERSB Sb:Ni:Va
[10]
0
GNI3SB_BETA = −6235.57 + 8.93666358T + 0.25 GHSERNI + 0.25 GHSERSB Sb:Va:Ni
[10]
0
GNI3SB_BETA = 5312 + 19.5T + 0.25 GHSERSB Sb:Va:Va
[10]
0 NI3SB_BETA LSb:Ni,Va:Va
= 2000 − 9.88685T
[10]
0 NI3SB_BETA LSb:Ni,Va:Ni
= 2000 − 9.88685T
[10]
0 NI3SB_BETA LSb:Ni:Ni,Va
= −7508.25 + 8.78T
[10]
0 NI3SB_BETA LSb:Va:Ni,Va
= −7508.25 + 8.78T
= −23310 + 19.82T − 3.50035T ln T + 0.00932581948T − 3.009 × 10 T + 0.333GHSERNI + 0.333 GHSERSBLOW
T + 7.414 ×
−6 3
[10]
GNISB_GAMMA = −16000 + 2T + 0.6667 GHSERNI + 0.3333 GHSERSB Sb:Ni:Ni
[10]
0
GNISB_GAMMA = 5522.55 + 1.3T + 0.3333 GHSERSB Sb:Va:Va
[10]
0
GNISB_GAMMA = −3182.1533 + 52.79T + 0.333 GHSERNI + 0.333 GHSERSB Sb:Va:Ni
[10]
= −1200 − 2T
[10]
0 NISB_GAMMA LSb:Ni,Va:Ni
= −1200 − 2T
[10]
0 NISB_GAMMA LSb:Ni:Ni,Va
= −13500 + 3T
[10]
0 NISB_GAMMA LSb:Va:Ni,Va
= −13500 + 3T
[10]
0
GNISB_DELTA = 3500 − 1.11 + GHSERNI Ni:Ni
0
GNISB_DELTA = −21460 − 1.31T + 0.75 GHSERNI + 0.25 GHSERSB Ni:Sb
[10]
0
GNISB_DELTA = −7252.56 + 11T Ni:Ni,Sb
[10]
0
GNI5SB2 = 2201.1 + 0.80005T + GHSERNI Ni:Ni
[10]
0
GNI5SB2 Ni:Sb = −23928.52 − 1.1T + 0.7143 GHSERNI + 0.2857 GHSERSB
0 NI5SB2 LNi:N,Sbi
NISB2 (Ni)0.3333 (Sb)0.6667
2
0
0 NISB_GAMMA LSb:Ni,Va:Va
NI5SB2 (Ni)0.7143 (Ni, Sb)0.2857
[10]
GNISB_GAMMA Sb:Ni:Va −21 7
10
NI3SB_DELTA (Ni)0.75 (Ni, Sb)0.25
[11]
0
0
NISB_GAMMA (Sb)0.3333 (Ni, Va)0.3333 (Va, Ni)0.3333
References
0 LIQUID LNi,Pb
0
[10]
= −7150 + 6T
GNISB2 Ni:Sb = −26020 + 4.43T + 0.3333 GHSERNI + 0.6667 GHSERSB
sublattice model [10]. The intermediate phases γ (NISB_GAMMA) and β (NI3SB_BETA), both with extensive homogeneity ranges, were described using three sublattices: (Sb) 1/3 (Ni%, Va) 1/3 (Va%, Ni) 1/3 and (Sb) 1/4 (Ni%, Va) 1/2 (Ni%, Va) 1/4. The two low-temperature phases δ (NI3SB_DELTA) and θ (NI5SB2), with narrow homogeneity ranges, were modeled as two sublattices: (Ni) 3/4 (Sb, Ni) 1/4 and (Ni) 5/7 (Sb, Ni) 2/7. The intermetallic compound ξ (NiSb2), with no homogeneity range, was treated as a stoichiometric compound [10]. The binary thermodynamic parameters used for the prediction of phase equilibria in the Ni–Pb–Sb system are listed in Table 2.
[10] [10] [10]
The calculated binaries Ni–Sb, Ni–Pb, and Pb–Sb are presented in Fig. 1. The binary Pb–Sb system represents a eutectic system, as well as the binary Ni–Pb system, having a miscibility gap in the liquid state. The binary Ni–Sb system is a complex binary system, in which nickel and antimony form several intermetallic compounds, and numerous reactions occur. 4. Literature data The ternary Ni–Pb–Sb system was experimentally investigated by Zeng and Lin [13]. They proposed the isothermal section of
D. Minić et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 35 (2011) 308–313
311
Table 3 DSC results of the investigated alloys of the ternary Ni–Pb–Sb system. Alloy composition
Phase transition temperatures (°C) Liquidus temperature
Fig. 2. Isothermal section of the ternary Ni–Pb–Sb system at 500 K [13].
x(Pb)
x(Ni)/x(Sb) = 1/3
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
980 1020 1087 1078 1261 1103 1285 1251 1087
x(Sb)
x(Ni)/x(Pb) = 1
0.5 0.6 0.7 0.8 0.9
1135 1009 861 808 742
x(Pb)
x(Sb) = 0, 6
0.1 0.15 0.2 0.25 0.3
1076 1065 1041 1023 943
Other phase transition
252; 527 252; 507 253; 483 250; 329; 450 252; 421 258; 379 261; 1096 257; 1092 250; 297
252; 450 250; 512 251 248 249
249; 525 247; 521 253; 501 252; 464 251; 479
The intensive thermal effect close to the predicted temperature of the ternary eutectic reaction at 252.4 °C is observed for all investigated samples. The experimentally determined liquidus temperatures for several investigated samples differ considerably from the predicted values. 5.2. Microstructure investigation results
Fig. 3. DSC curve for the Ni15 Pb25 Sb60 alloy with determined phase transition temperatures.
the Ni–Pb–Sb ternary system at 500 K, constructed using Xray diffraction (XRD) and metallographic results. There were five three-phase regions, eleven two-phase regions, and seven singlephase regions in that section (Fig. 2), and the maximum solid solubility of Sb in Ni was about 6.25 at.% Sb. The maximum solid solubility of Sb in Pb was about 3.9 at.% Sb. The homogeneity range of NiSb extended from about 49 to 52.3 at.% Sb at 500 K. No ternary compounds were reported. 5. Results and discussion
The compositions of coexisting phases of three samples, equilibrated at 700 °C, were investigated using the SEM–EDS method. Their overall compositions and experimentally determined compositions of coexisting phases are given in Table 4. The maximum experimental error in determined phase compositions is within the range ±4 at.%. The calculated isothermal section of the ternary Ni–Pb–Sb system at 700 °C and experimentally determined phase composition for samples 1, 2 and 3 are presented in Fig. 5 for comparison. Three alloys were examined: two of them from the twophase region (LIQUID+NISB_GAMMA) and one from the threephase region (NISB_GAMMA+LIQUID+NI3SB_BETA). The calculated equilibria and experimental values obtained by SEM–EDS method show good agreement. The SEM microstructure of sample 3, with phases marked, is presented in Fig. 6.
5.1. Thermal analysis results
5.3. Predicted liquidus projection and invariant equilibria
In order to experimentally study the phase transition temperatures of the Ni–Pb–Sb ternary system and to make a comparison with the thermodynamic predictions, alloys along three chosen vertical sections with molar ratio x(Ni) : x(Sb) = 1 : 3, x(Ni) : x(Pb) = 1, and x(Sb) = 0.6, were investigated using DSC. The temperatures of invariant phase transitions were taken from the extrapolated peak onset on heating. The other phase transition temperatures were taken from the peak temperature. The overall DSC results from this work are given in Table 3. The DSC thermograph for the alloy Ni15 Pb25 Sb60 is presented in Fig. 3. The predicted vertical sections and experimentally obtained phase transition temperatures are shown in Fig. 4(a)–(c).
The extrapolated liquidus projection of the Ni–Pb–Sb ternary system is plotted in Fig. 7. The calculated liquidus projection shows a large composition region of liquid immiscibility. Two ternary monotectic reactions (E1 and E2), with the ternary monotectic points located close to the Ni–Sb boundary system, were predicted in this system. A ternary eutectic reaction (E3), with ternary eutectic point situated very close to the Pb–Sb binary eutectic point, was calculated to be at 252.4 °C. This temperature represents the lowest temperature of thermodynamic stability of the liquid phase in this ternary system according to the thermodynamic prediction. This eutectic reaction was experimentally confirmed by DSC results from this study (Table 3). However, the predicted Pb-rich part of the liquidus projection is very doubtful. It includes
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D. Minić et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 35 (2011) 308–313
Fig. 4. Calculated vertical sections of the Ni–Pb–Sb ternary system compared with DSC results from the present study: (a) x(Ni) : x(Sb) = 1 : 3, (b) x(Ni) : x(Pb) = 1, and (c) x(Sb) = 0.6.
Table 4 Calculated and experimentally determined phase compositions for the ternary Ni–Pb–Sb system at 700 °C. Overall composition (at.%)
Theoretic predicted phases
LIQUID NISB_GAMMA LIQUID NISB_GAMMA NI3SB_BETA LIQUID NISB_GAMMA
18.4 Pb 20.6 Ni 61 Sb 20 Pb 49 Ni 31 Sb 38 Pb 20.5 Ni 41.5 Sb
Experiment determined phases
LIQUID NISB_GAMMA LIQUID NISB_GAMMA NI3SB_BETA LIQUID NISB_GAMMA
Exp. compositions of phases (at.%) Ni
Pb
Sb
1.92 ± 0.92 45.53 ± 1.23 2.95 ± 2.47 53.53 ± 0.09 68.87 ± 1.96 1.13 ± 0.773 48 ± 0.61
33.77 ± 0.97 1.34 ± 1.06 95.27 ± 3.99 0.69 ± 0.69 1.36 ± 1.36 65.93 ± 1.01 0,65 ± 0.22
64.31 ± 0.04 53.13 ± 0.17 1.78 ± 1.53 45.78 ± 0.78 29.77 ± 0.6 32.46 ± 0.24 51.35 ± 0.38
Table 5 Predicted invariant reactions in the Ni–Pb–Sb ternary system (outside the Pb-rich composition region). Type
T (°C)
Reaction
E1 E2 E3
1079.2 1060.1 252.4
LIQUID → LIQUID + NI3SB_BETA + FCC_A1 LIQUID → LIQUID + NI3SB_BETA + NISB_GAMMA NISB_GAMMA + RHOMBO_A7 + FCC_A1 → LIQUID
a
The composition of LIQUID is very close to that of the boundary of the Pb–Sb system.
Composition (at.%) Ni
Pb
79.4 60.9 0a
3.1 3.3 82.2
D. Minić et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 35 (2011) 308–313
Fig. 5. Predicted isothermal section of the ternary Ni–Pb–Sb system at 700 °C and experimental values of the phase compositions for the samples 1, 2, and 3.
313
Fig. 7. Predicted liquidus projection of the ternary Ni–Pb–Sb system.
has been conducted using DSC and SEM–EDS. The experimental results were compared with the results of thermodynamic binarybased prediction. The calculated isothermal section at 700 °C shows reasonable agreement with the results of the SEM–EDS analysis. The melting behavior of the different Ni–Pb–Sb alloys has been determined. A ternary eutectic at 252.4 °C was experimentally verified. The experimental results reported in this study can be used for further thermodynamic assessment of phase equilibria in the Ni–Pb–Sb ternary system. Acknowledgments This work was supported by the Ministry of Science of the Republic of Serbia (Project No. OI172037). Appendix. Supplementary data Fig. 6. SEM microstructure of alloy 3.
the primary crystallization fields of the binary intermetallic phases from the boundary Ni–Sb binary system (NI3SB_BETA and NISB_GAMMA) and very small fields (NISB_DELTA, NI5SB2, and NISB2), visible only under magnification, all located very close to pure Pb. These predicted primary crystalline phases and related predicted ternary invariant reactions were not verified experimentally in the present study, and are not indicated in Fig. 7 and in Table 5. 6. Conclusion The phase equilibria in the Ni–Pb–Sb ternary system were extrapolated using optimized binary thermodynamic parameters. The predicted phase diagram shows a large composition region of liquid immiscibility and the existence of three E-type reactions. The predicted phase equilibria in the Pb-rich corner (very close to pure Pb) of the ternary diagram are doubtful, and are not in agreement with the binary phase equilibria, which indicates that the ternary interactions are significant. A preliminary experimental investigation of Ni–Pb–Sb ternary phase diagram
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