A thermodynamic assessment of the iron — Antimony system

C&M Vol. 19, No. 1, pp. l-15,1995 Copyright 0 1995 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0304-5916/95 $9.50 + 0.00

0364-5916(95)

00001-I

A THERMODYNAMIC ASSESSMENT OF THE IRON - ANTIMONY SYSTEM Benyan Pei*, Bo Bjhkman*, Bo Sandman** and Bo Jamson** * Division of Process Metallurgy, Lul& University of Technology, S-97 187 Lule$ Sweden **Division of Applied Thexmadynamics, Royal Institute of Technology, S-100 44 Stockholm, Sweden

ABSTRACT

A critical assessment of the Fe-Sb system was carried out by using a computerized technique. Both the liquid and solid solution phases were described by regular solution models. Nonstoichiometric phase, &-FeSb, was modeled as (Fe)(Fe,Sb), and FeSb, was treated as a stoichiometric compound. A set of parameters describing the Gibbs energies of the different phases was optimized by using the existing phase diagram information and thermodynamic properties under one atmosphere. Assessed phase diagram and thermodynamic data are presented and compared with experimental data.

Introduction The iron - antimony binary system has been subjected to many extensive studies. For example, phase equilibrium information was subsequently reviewed by Hansen and Anderko [ 11,Shunk [2], Kubaschewski [3] and most recently by Okamoto [4], who took into account phase diagram, crystal structures, lattice parameters and thermodynamics. Hultgren [5,6] reviewed and collected some thermodynamic data for the system. According to Okamoto [4], the phase boundaries in the Fe-Sb system have been well established. The system is characterized by two intermetallic phases, c-FeSb phase and FeSb, phase, and two terminal solid solutions of Sb in fle(FCC) and in uFe(BCC). &Fe and aF& form a continuous phase field, aFe(BCC), surrounding the y-loop. The &-FeSb phase is nonstoichiometric with composition range between about 40 and 47 at.% Sb. Up to now, there is no thermodynamic modeling of the system available. The purpose of the present work was to assess the system by thermodynamic models which couple together phase diagram and thermodynamic data. Such assessment would produce a mathematical description of the thermodynamic properties and phase equilibrium information of the Fe-Sb system. The present work would also supplement as:sessment of binary systems in the pentanary (quinary) system Cu-Fe-S-As-Sb which is relevant to copper smelting process. The assessment of Cu-As, Fe-As systems has been finished and reported elsewhere [7,8].

Original version received on 24 September 1993, Revised version on 15 July 1994

1

B. PEI et al.

Thermodynamic Modeling The liquid phase and the terminal solid solutions of Sb in aFe(BCC)

and in yFe(FCC) were described by

substitutional regular solution models. The Gibbs energies of such solutions are expressed as:

G, = XFeOGFe +XSb‘G,b+ RVX,J~, XF,XSbit

+ X,,msb)

kLFe, Sb@Fe - Xsdk

(1)

kc0

The Xre and X,, are the mole fractions of iron and antimony, respectively. ‘GFe and ‘G,, are the Gibbs energies of pure iron and antimony

in the respective phases relative to their reference phase, BCC and Rhombohedral,

respectively, at 298.15 K. The term with RT is the idea1 Gibbs energy of mixing and the last term is the excess Gibbs energy of mixing which could be represented by Redlich-Kister polynomial. For the aFe(BCC) and yFe(FCC) phases, the magnetic contribution

to the total Gibbs energy, Gtg, is given by

equation (2) according to Hillert and Jar1 [9]: Gig = RTln(B + l)f(r),

r=T/Tc

(2)

where f(r) is a polynomial [9] and will be presented in detail in a later section. Tc is the Curie temperature and B the magnetic moment, which is related to the total magnetic entropy by equation (3): ASmg= Rln(B + 1)

(3)

The Curie temperatures and magnetic momenta for the uFe(BCC) and yFe(FCC) phases were taken from the SGTE database [lo]. The nonstoichiometric

phase, a-FeSb, has a hexagonal, B8, type (NiAs type) structure. Its homogeneity range

deviates from FeSb to the Fe-rich side. A two sublattice model, (Fe)(Fe,Sb), with interstitial Fe on the Sb sublattice was applied for this phase. The Gibbs energy according to this compound energy model is:

+ YS&Ysb) Gm= YFeOGFe:Fe + YSbOGFe:Sb+RT(yFelnyFe YFe&bkc

k&e

:Fe,

Sb(YFe

%dk

(4)

The first term, ‘GFs :Fe, is the double Gibbs energy of pure Fe in a-FeSb phase. It was taken from SGTE database [ 101 as equivalent to the data for the HCP_A3 phase. The second term, ‘GFe: sb, is the Gibbs energy of a-FeSb phase at stoichiometric composition, FeSb. The yFe and ySb are the site fractions of Fe and Sb in the Sb sublattice, respectively. The last term is the excess Gibbs energy, Gr, which represents interaction parameters, kLF, : Fe, sb, in the Sb sublattice.

THERMODYNAMIC

The compound FeSb, is a stoichiometric

ASSESSMENT

OF Fe-Sb

SYSTEM

phase with an orthorhombic structure. Its standard Gibbs energy of

formation from pure elements Fe and Sb was described as a linear function of temperature in equation (5): AG = ‘GFeSb - ‘GFF - 2 ‘Gzy. 2

= A + B*T (J/mol)

(5)

for the reaction: Fe + 2 Sb = FeSb,

Phase Diagram Information The current accepted Fe-Sb phase diagram is from Kubaschewski [3] and Okamoto [4]. Accordingly, antimony has two terminal s(Dlidsolutions in iron, one in aFe(BCC) and another in yFe(FCC). The solid solution of Sb in yFe(FCC) is characterized by a closed field (y loop). The (a + yFe)/uFe boundary was reported to lie at about 2.1 at.% Sb [ 111 or between 0.7 and 1.4 at.% Sb at 1423 K [12]. Vogel and Dannijhl[13] and Svechnikov’and Gridnev [14] reported the solubility of Sb in yFe(FCC) at 1423 K to be 0.93 at.% Sb. More accurate data were reported by Hillert et al [15] who found that their experimental results satisfy very well van? Hoff’s equation, as might be expected from the relatively low concentration of Sb in yFe(FCC). As reviewed by Hansen and Anderko [ 11, the solid solubility of Sb in aFe(BCC) was not accurately determined before 1958. Later investigations produced much better consistent data. These data are from Predel and Frebel [ 163 who employed1 X-ray and DTA analyses, Nageswararao et al [17] who measured lattice parameters, and Takayama et al. [ 181 who based their results on X-ray diffraction and electroprobe microanalyses. Kubaschewski [3] chased the data from Takayama et al [ 181 for the construction of solvus. Okamoto [4] used the data by F?edel and Frebel [ 161, Nageswararao et al [17],and Takayama et al [ 181 for solvus. Baaed on optical microscopy, Feschotte and Lorin [19] reported much higher solubilities of Sb in aFe(BCC) than others [16 - 181, possibly because that their data were overestimated. Their data were not used in this assessment. The Liquid t) uFe(BCC) + &-FeSb eutectic data adopted by both Kubaschewski [31 and Okamoto 141are the same, 1269 K at 34.6 at.% Sb from Maier and Wachtel[201 who studied the system by means of magneto-thermal

analyses supported by X-ray and DTA measurements

in the

temperature ra.nge 493 - 1873 K. Galasso et al [21] reported the same eutectic data as Maier and Wachtel[20]. The liquidus curves determined by thermal analyses [13,22,23],

magneto-thermal analyses [20] and EMF-method [24]

are in substantial agreement. The mono-antimonide,

E-FeSb phase (NiAs-type), melts congruently. The congruent melting point was reported by

various authors with different data 141. For the reason of consistency, the result (1292 K at 42 at.% Sb) given by Maier and Wachtel[20] was accepted by both Kubaschewski [3] and Okamoto 141.The composition range of e-FeSb was determined by a number of investigators. Kjekshus and Walseth 1251based their results at temperatures from 573 to 1273 K on the X-ray, density and metallographic studies. Their results agree reasonably with the data determined by thermal analysis [ 131, lattice parameter measurements [26], and Knudsen cell methods [27]. The data by Ageev and Makarov (X-ray metallography) [ZS], Maier and Wachtel (thermal) [20], Gerasimov(EMF) 1291and Feschotte and Lorin (metallography) [ 191 differ slightly from others [13,26,27].

6. PEI eta/.

The stoichiometric phase, FeSb,, is formed peritectically at 1011 K with a-FeSb at about 47 at.% Sb and liquid at 88.8 at.% Sb. Kubaschewski [3] quoted the eutectic temperature between FeSb, and pure Sb(Rhombohedral) as 887 K [20], and Okamoto [4] assessed it as 901 K, which is in agreement with Kurnakov [231. The aFe(BCC) solidus is not well defined. The data by Maier and Wachtel[20] were excluded because the values are not in accord with the well defined solvus. Okamoto [4] drew the boundary by assuming 5 at.% solubility of Sb in aFe(_BCC) at eutectic temperature. The initial slope of the solidus at 0 at.% Sb is about - 48 K/at.% Sb [4], which was calculated from the liquidus slope using the van? Hoff equation with 13.8 kJ/mol[30] for the enthalpy of fusion of uFe(BCC). Okamoto [4] also calculated the initial slope of the aSb(RHOM.) liquidus as about - 3.4 K/at.% Sb according to the van? Hoff equation assuming 19.9 kJ/mol[301 for the enthalpy of fusion of Sb and no solubility of Fe in aSb.

Magnetism The Curie temperature of pure u.Fe is 1043 K [31]. The effect of Sb on T, of aFe(BCC) is not significant. The detail composition dependence of Tc has not been measured. Tc of aFe + s-FeSb two phase region is 1038 K [20]. For the s-FeSb phase, early detected transformation at 893 K 1201was not confirmed by Maier and Wachtel[201. Instead, they found a magnetic transformation at about 493 K. The magnetic transformations

of uFe(BCC) and yFe(FCC) were considered in the thermodynamic modeling. The

simple linear variation of the Curie temperature with composition was assumed. The magnetic susceptibilities FeSb, were measured by Maier and Wachtel [20] and by Rosenqvist

[321. According to Rosenqvist

of

[321,

antiferromagnetic was observed for samples quenched from 973 K and superimposed ferromagnetism was obtained for slowly cooled samples below 773 K. Maier and Wachtel[20] found ferromagnetic behavior below 838 K in the annealed state and paramagnetic behavior in the quenched state. The magnetic properties of e-FeSb phase and FeSb, were, however, not considered in the present evaluation. All the crystal structure data and lattice parameters in the system have been summarized by Okamoto [41.

Thermodynamic Data In the present work, the thermodynamic data of pure iron and antimony were taken from SGTE databank [lo] and are listed in Table 1. The reference state for the Gibbs energy data (Table 1) is the stable state at 298.15 K and 1 bar. It is denoted as SER in this paper. Hultgren [5,6] summarized some thermodynamic

data for the Fe-Sb system from the literature [33, 343. Early

calorimetric measurements of heat of the formation by KLirber and Gelsen [33] were excluded because of uncertainty as to the phase presented in their studies. Geiderikh et al. [34] studied the system at temperatures 673 - 873 K for the composition range FeSb, + Sb and 773 - 973 K for the rest of the composition by EMF-method. From the measured

THERMODYNAMIC

ASSESSMENT

OF Fe-Sb SYSTEM

Table 1. Gibbs energy data of pure antimony and iron from SGTE databank [8], with rference to SER (stable element reference) at 298.15 K and 1 bar, J/mol. Fe(BCC), SER State 298.15~(K)<1811.00 OG’scc- HSER= +1225.7+124.134T-23.5143Tln(T)4.39752~10~3T2+77359T~1-5.8927~ I”e Fe

lo-sT3;

1811.OOcT(K)<6OOO OGE~CC

I’e

Hzy = -25383.581+299.31255T-46.OTln(T)+2.29603~1031T~g.

-

Fe(FCC) 298.15cT<1811.00 ‘GrcC E’e - HSER Fe = -236.7+132.416T-24.6643Tln(T)-3.75752~10~3T2+77359T~1-5.8927.10~8T3; 18 11.OO
=

-2480.08+136.725T-24.6643Tln(T)-3.75752~10-3T2+77359T-1-5.8927~10-*T3;

1811.00~<6000 ‘GHCP - HEF = -29340.78+304.56206T-46.OTln(T)+2.78854~10t31T-g+GHSERFE. Fe Fe(liquid) 298.15
- HEER= 132&X87+1 17.57557T-23.5143Tln~)-4.39752.10-~T2-5.89269.10-8T3 +77358.5T-1-3.6751551.10-21T7;

181 LOO(r(K)<6000

OGLiq. Fe

- Hi:” = -10838.83+291.302T46.OTln(T).

Sb(Rhombohedral), SER State 298.15
=

-9242.858+156. 154689T-30.5130752Tln(T)+7.748768~10~3T2-3.003415~10~6T3

+100625T-1; 903.78&(K)<2000 OGR-IOM. S3

HEp = -11738.83+169.485872T-31.38Tln(T)+1.6168~1027T~g.

Sb(liquid) 298.15
OGBCC_ Sb

‘G;r”.

= 19874-15.1T;

B. PEI et al.

EMF-temperature

relations, they calculated both partial and integral Gibbs energies, entropies and enthalpies of

mixing for the system. The determined enthalpies of formation of FeSb, and Fe,. ,,Sb,. 4s are - 9.62 and - 5.02 kJ/g-atom, respectively. Predel and Vogelbein [35] measured the enthalpies of formation of the a-FeSb phase at 1060 K and 45 and 43 at.% Sb to be about 2.999fl.385

and - 0.044&l .234 kJ/gatom respectively.

These data were

excluded in this assessment due to the fact that the uncertainties with their data are very high. Besides, it is very unlikely that the enthalpy of formation for a-FeSb is positive or close to zero. Dynan and Miller [271 measured Sb activities in the solid Fe-Sb alloys by the Knudsen-cell

technique with

temperature varying from 800 to 1140 K and corresponding composition from 30 to 70 at % Sb. The Fe activities were calculated by Gibbs-Duhem equation and assuming that the activity of Sb obeyed Henry’s law in the terminal iron-rich solution and Raoult’s law in the terminal Sb-rich solution. Both integral and partial molar quantities were calculated over the entire composition range at 893 K. The composition range of a-FeSb phase was found to be from 42.1 to 46 at.% Sb by observing the continuous decrease in activity. Tomilin [36] determined the Sb activities in solid aFe by study of Sb distribution between liquid Pb and solid Fe at temperatures 1032.1109 and 1150 K. The Sb activities in aFe show positive deviations from the ideal state and obey Henry’s law in a large range of composition. Tomilin [36] also determined the Sb activities in the liquid Fe-Sb alloys at 1823 K with compositions from 0 to about 4 at.% Sb. Positive deviations were also found for the Sb activity in the liquid phase. By using EMF method, Vecher et al 1241measured Fe activities in the liquid Fe-Sb alloys at temperatures from 900 to 1141 K and compositions

from 76.7 to 98.5 at.% Sb. The Sb activities were calculated by Gibbs-Duhem

integration. The Fe activities with solid aFe(BCC) as standard state show positive deviations from the ideal state.

Optimization Procedure and Calculation Prior to carrying out the optimization, a careful analysis of the literature data was made. The reported liquidus data show in fairly good consistency and were all used in the assessment. The experimentally determined solvus data [16-181 agree very well with each other and were used in the assessment. The solidus data were taken from Kubaschewski [3]. The thermodynamic data of solid phases, aFe(BCC), a-FeSb and FeSb, by Geiderikh et al [341 and Dynan and Miller 1271 were applied. The activities of Sb in aFe(BCC) phase by Tomilin [36] were used. The liquid phase activities by Vecher et al. [24] and Tomilin [36] were selected. All the selected data were given a certain weight by carefully judging their accuracy, so that the best fit of all the experimental data could be achieved. All the model parameters given in Eqs. (1) to (5) were evaluated in the optimization procedure by using the PARROT program [37], which is based on least square analysis. All the assessed parameters are given in Table 2. Once all the parameters were obtained, the Fe-Sb phase diagram as well as other thermodynamic properties were calculated by using the program POLY3 1371,which is baaed on the conditions that the partial Gibbs energies of the component elements for a two-phase equilibrium are equal at constant temperature and pressure. The comparison between the calculation and the experimental data is discussed in the following.

THERMODYNAMIC

ASSESSMENT

OF Fe-Sb SYSTEM

Table 2. The optimized parameters describing the thermodynamic properties of the Fe-Sb system. The values are given in joule per mole of formula unit. The magnetic contribution to Gibbs energy is described by mcGm= RTln(@ + l)f(r), z = Tflc for z
- Hi:” (SGTR data in Table 1)

‘Gsb - Hir

- Hir

= ‘GiF*

(SGTE data in Table 1)

OLFe Sb= -22891.21 + 17.47T lLFe'Sb= -15222.54 + 8.74T 2Lr.’ , Sb

=

2336.64

a-Fe(BCC_Al)

phase, (Fe,Sb)

OGFe- H;fR = OG;r - Hi:” (SGTR data in Table 1) OGSb-

OLF,

HzER= ‘Gir Sb =

lLFe'Sb I =

- Hir

(SGTE data in Table 1)

4764.10 + 26.28T -35112.52

,pFe(FCC_A2) phase, (Fe,Sb) ‘GFe - H;F = ‘Gf: ‘G,, - Hir

- Hi?

(SGTE data in Table 1)

= ‘GEr - Hir

(SGTE data in Table 1)

“LF=,sb =2684.10+21.15T lLFe I Sb = -21095.63 :s-FeSb phase, (Fe)(Fe,Sb) oGFe:Fe-20G;~=0 ‘Gr,: Sb - ‘G;zP - ‘G;r ‘3Lre:Fe

Sb=

LLF.:Fe'Sb , =

= -32715.38 + 7.OOT

16407.28 + 4.393 26981.65

:FeSb, phase, (Fe)(Sb), “GFeSb - ‘G;r

- 2 ‘G;p.

= -30186.21+ 9.15T

Experimental data: ‘GFeSb - ‘GFzC - 2 ‘Gy. 2

= -28894.54 + 7.72T (6OGeiI341)

B. PEI et a/.

Table 3. Invariant equilibria in the assessed Fe-Sb system Reaction

Temperature Reaction

Composition of the respective phases, at.%

a-FeSb = L &-F&b = L a-FeSb = L L = a-Fe + a-FeSb L = a-Fe + a-FeSb L = a-Fe + a-FeS b L + a-FeSb = FeSb, L + s-FeSb = FeSb, L + c-FeSb = FeSb, L = FeSb, + a-Sb L = FeSb, + a-Sb L = FeSb, + a-Sb

0

32.52 34.60 34.60 89.49 88.80 88.80 98.12 99.20 99.20

0.2

42.58 42.00 42.00 5.26 5.00 5.00 48.45 46.50 47.00 66.67 66.67 66.67

40.72 39.00 40.00 66.67 66.67 66.67 100 100 100

0.6

0.4

T(K)

type

1290 1292 1292 1271 1269 1269 1019 1011 1011 898 887 901

Congruent Congruent Congruent Eutectic Eutectic Eutee tic Per&tic Peritectic Peritectic Eutectic Eutectic Eutectic

0.8

1.0

X Sb Fig. 1. The calculated Fe-Sb phase diagram in comparison with the experimental data.

Reference

This work 82Kub[3] 900ka[4] This work 82Kub[3] 9OOka[4] This work 82Kub[3] 900ka[4] This work 82Kub[3] 900ka[4]

THERMODYNAMIC

ASSESSMENT

OF Fe-Sb SYSTEM

1800 1700 1667

1600 kfi . t.? s t: i% E g

1500 1400 1300 1200 1185

1100

E-3

X Sb

Fig. 2. The calculated y-loop (a + y Fe) with the superimposed experimental data.

1500 1400

*_ 1100 p! i 1000 k

900

’

800

(uFe)+(c-FeSb)

700 600 0.40 X Sb Fig. 3. The enlarged section around congruent melting of the &-FeSb phase, symbols as in Fig. 1.

B. PEI et al.

10

3

E” 950 -

G

FeSb, + Liquid

*

*

*

*

FeSb, + (aSb)

@.Sb) +

I 0.90

045

I 0.95

1.oo

X Sb Fig. 4. Enlarged Sb-rich part of the phase diagram, symbols as in Fig. 1.

I

35

I

I

&OTom[36](1032

30 -

I

I

100

125

K)

C36OTom(36](1109 K) 06OTom[36](

1150K)

25 20 15 -

0

25

50

75

150

x,,. 1o4 Fig. 5. The calculated Sb activity in the solid aFe(BCC) phase at 1100 K in comparison with the experimental data, standard state: RHOM.(Sb).

THERMODYNAMIC

A

0

OF Fe-Sb

ASSESSMENT

0.2

0.4

0.6

SYSTEM

0.8

X Sb Fig. 6. The calculated and experimental activities in the solid phases at 893 K, standard states: BCC(Fe) and RHOM.(Sb).

A75Dyn[27](893

ql6oGei[341(830

I

K) K)

(aFe) + (&-F&b)

X Sb Fig. 7. The calculated enthalpy of mixing at 893 K in comparison with the experimental values, standard states: BCC(Fe) and RHOM.(Sb).

11

1.0

B. PEI et al.

12

I

1.0

I

I

I

I

0.6

0.8

I

0.9 -------

0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0

0.2

0.4

1.0

X Sb Fig. 8. The calculates activities in the liquid phase at 1125 K (standard states: BCC for aFe and liquid Sb for a& and 1823 K (standard states: liquid Fe and Sb).

-25 0

I

I

I

I

0.2

0.4

0.6

0.8

‘Sb

Fig. 9. The calculated enthalpy of mixing at 1125 K, stardard states: liquid Fe and Sb.

1.0

THERMODYNAMIC

ASSESSMENT

OF Fe-Sb SYSTEM

13

Discussion The calculated phase diagram is shown in Fig. 1. All the available experimental

data are plotted as well for

comparison. The enlarged detail y-loop, congruent melting area of e-FeSb and Sb-rich part of the phase diagram are shown in Fi8s. 2 - 4. The calculated phase diagram agrees very well with the experimental data in most part. Two solidus points by Maier and Wachtel [20] differ much from the assessment. These two points were disregarded because of the inaccuracy. Three solvus points given by Feschotte and Lorin [ 191 disagree from other data and the calculation. These data were rejected as well in the assessment. All the invariant equilibria are summarized in Table 3 and compared with those given by Kubaschewski [3] and Okamoto 141.As seen, the agreement is fairly good. The present calculated y-loop agrees well with the data by Hillert et al [15] and the boundary assessed by Kubaschewski [3]. Early data [ 11, 12, 143reviewed by Hansen and Anderko [ 11are regarded less reliable. For the composition range of the s-FeSb phase, the calculated boundaries do not follow the experimental data exactly, but in a close and reasonable pattern. The calculation implies that the s-FeSb phase has wider composition range than the experimental data indicated. The Sb activity at 1100 K in aFe(BCC) was calculated and is given in Fig. 5. The calculated values agree well with the experimental data [36]. The Sb activities show positive deviations from the ideal state. The calculated value appears as a slight concave curve as Sb concentration increases. However, the experimental data [36] obey Hemy’s law in the composition range. More experimental data are desirable to verify the Sb activity behavior in the solid aFe(BCC) phase. In order to compare with the data given by Dynan and Miller [27] and by Geideiikh et al [34], the Sb and Fe activities at 893 K were calculated and are shown in Fig. 6 for the whole composition range. The calculated values agree generally well with the experimental data. The calculated composition range of a-FeSb phase at 893 K is slightly wider than what the experimental

activities indicate. But the disagreement

is regarded as within the limit of

experimental error. The calculakd enthalpy of mixing at 830 K in the solid phase is given in Fig. 7. As seen, the calculated values agree very well with the experimental data by Geideiikh et al [34], but not well with the data by Dynan and Miller [27] at composition of the FeSb, and e-FeSb phase range. The calculated value at FeSb, differs by about 2.4 k.I, and even less in &-FeSlb range from the data by Dynan and Miller [27]. Such disagreement is not regarded as significant. The assessed Gibbs energy of formation of FeSb, agrees reasonably well with the experimental determined data [34] (Table 2). The calculated activities in the liquid phase at 1125 and 1823 K are shown in Fig. 8 in which are experimental data given as well. The agreement between the calculation and experimental data is good. Positive deviations from the

B. PEI et al.

Raoult’s law are indicated. Fig. 9 shows the enthalpy of mixing of the liquid phase, the calculated cmve agreeing well with the experimental determined data [24]. There are few data in the dilute solution with low Sb concentration. Further experimental

work is desired to determine the Fe and Sb activities and the enthalpy of mixing in dilute

solution at various temperatures.

Acknowledgments This work was a part of the project-Thermodynamic

assessment of the Cu-Fe-S-As-Sb system, which belongs to the

consortium CAMPADA - Computer Assisted Material and Process Development, financially supported by NUTEK.

References 1. M. Hansen and K. Anderko, Constitution of Binary Alloys, McGraw-Hill, New York(1958), p. 708 - 710. 2. F.A. Shunk, Constitution of Binary Alloys, Second Supplement, McGraw-Hill, New York(1969), p. 346. 3.0. Kubaschewski, Iron-Binary Phase Diagrams, Springer-Verlag, New York(1982), p. 128 - 130. 4. T.B. Massalski, P.R. Subramanian, H. Okamoto and L. Kacprzak, Binary Alloy Phase Diagrams, 2nd ed., 2. ASM International, Materials Park, OH(1990), p. 1763 - 1767. 5. R. Hultgren, R.L. Grr, P.D. Anderson and K.K. Kelley, Selected Values of the Thermodynamic Properties of Metals and Alloys, John Wiley and Sons, New York(1963), p. 739 - 740. 6. R. Hultgren, P.D. Desai, D.T. Hawkins, M. Gleiser and K.K. Kelley, Selected Values of the Thermodynamic Properties of Binary Alloys, ASM, Metals Park, OH( 1973), p. 868 - 870. 7. B. Pei, B. Bjokman, B. Jansson, B. Sundman, Z. Metall. &(1994), p. 171-177. 8. B. Pei, B. Bjokman, B. Jansson, B. Sundman, Z. Metall. &(1994), p. 178-184. 9. M. Hillert and M. Jail, Calphad, 2,(1978), p. 227. 10. A. Dinsdale, SGTE Dam for Pure Element, Calphad =(1991), 11. W.D. Jones, J. Iron Steel Inst. m(1934),

p. 317-42.5.

p. 429 - 437.

12. P. Foumier, Rev. chim. ind., &(1935), p. 195 - 199. 13. R. Vogel and W. Dannohl, Arch. Eisenhiittenwes. &l,l(1934), p. 39 - 40. 14. V.N. Svechnikov andV.N. Gridnev, Metallurg,U(1938),

p. 13 - 19.

15. M. Hillert, T. Wada and H. Wada, J. Iron Steel Inst. 245(1967), p. 539 - 546. 16. B. Predel and M. Frebel, Arch. Eisenhiittenwes., Qo(1971).

p. 365 - 373.

17. M. Nageswararao, C.J. McMahon, Jr., and H. Herman, Metall. Trans., m(1974), 18. T. Takayama, M.Y. Wey and T. Nishizawa, Tran. Jpn. Inst. Met., m(1981), 19. P. Feschotte and D. Lorin, J. Less-Common Met., m(1989), 20. J. Maier and E. Wachtel, 2. Metallkd., -(1972),

p. 315-325.

p. 255 - 269.

p. 411 - 418.

21. F.S. Galasso, F.C. Douglas, W. Darby and J.A. Batt, J. Appl. Phys., u(1967), 22. W. Geller, Arch. Eisenhtittenwes., U(1939),

p. 1061 - 1068.

p. 263 - 266.

p. 3241 - 3244.

THERMODYNAMIC

ASSESSMENT

OF Fe-Sb SYSTEM

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