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Temperature-composition diagrams in the Ag2 (VIb)-(Vb) sections of the ternary Ag-(Vb)-(VIb) systems
P7
Journal of the Less-Common Metals, 58 (1978) P7 - P12 @ Elsevier Sequoia S.A., Lausanne - Printed in the Netherlands
TEMPERATURE-COMPOSITION SECTIONS OF THE TERNARY B. GATHER
DIAGRAMS Ag-(Vb)-(VIb)
and R. BLACHNIK
Anorganische Chemie, FB 8, Gesamthochschule Siegen 21 (F.R.G.) (Received
IN THE Ag, (VIb-(Vb) SYSTEMS*
Siegen, Adolf Reichwein
Str., 5900
July 26, 1977)
Summary The T-x sections AgsVIb-Vb were determined by differential thermal analysis, X-ray and metallographic methods. Three categories of phase diagrams have been found. The first consists of quasibinary systems of eutectic type, the second has eutectic behaviour with an additional miscibility gap and in the third the systems are not quasibinary.
1. Introduction In the course of investigations [ 1, 21 in our laboratory of the thermal properties of ternary chalcogenides, the cross sections AgaVIb-Vb were determined in order to get some preliminary results on the topology of the ternary systems Ag-Vb-VIb.
2. Experimental The experimental techniques were described in an earlier publication [ 31. The purities of the elements which were used in the preparations are given in Table 1. The annealing temperatures were 250 “C! for the bismuth systems and 500 “C for the others. The mixtures were annealed for 14 d.
3. Results The T-x diagrams AgsVIb-Vb were constructed from DTA measurements and metallographic examinations of the samples and are presented in
*Vb
= As, Sb, Bi; VIb = S, Se, Te.
P8
~__
Anf,mooy -----------
-._---_z
c
(a)
Af12S
,n 10
mot “I, moi
%
MO
Ag2T@ 20
40 hirenic
60 ,n
mot
.4Q %,
As
40
20 tiny &2Te
60
80
#n mot
Ol.3
in
moi
56
20
40 Bismuth
60 tn
mof
80
81
0
%
“/.,
(cl
Fig. 1. Temperature-composition diagrams in the Ag,(VIb j(Vb) sections of the ternary Ag-(Vb)-(VIb) systems: (a) the Ag$3 systems; (b) the AgzSe systems; (c) the AgzTe systems.
P9
TABLE Purity
1 of the elements
Element
Purity
&
99.999
Se, Te, Sb, Bi S
99.995 99.5
TABLE Thermal
(%)
Source Degussa Preussag Merck
2 data for the Ag@-As
V (mol.%)
10.2 19.8 30.1 40.5 49.9 59.8 70.0 80.0 89.9
system
Tliq
T cut
To+@
Q-r
(“C)
(“0
(“C)
(W
(“0
730 675 630 -
1003 948 903 -
626 640 655 690 737
899 913 928 963 1010
614 611 608 610 610 613 613 613 613
181
583 583 582 584 581 583 582 582 583
Figs. l(a) - l(c); the relevant data from the experiments are given in Tables 2 - 4. The AgzS-As diagram includes the data of Roland [ 41, which were obtained by metallographic analysis of quenched samples. In spite of the fact that the exper~ent~ methods of the two investigations were quite different, the agreement is fairly good. All mixtures, except those of AgaSAs and AgzTe-Sb which are eutectic, have a miscibility gap in the liquid state. The crystallization in the Ag,Te-VIb systems and in the mixtures Ag,Se-Bi and AgzS-As is quasibinary; the mixtures of Ag,Se with antimony and arsenic behave as pseudobinary systems. In the case .of the AgaS-VIb mixtures with antimony and bismuth, ternary c~stallization was observed. In these latter diagrams a complete interpretation of the effects could not be given without further measurements in the ternary system; these results will be reported in a future paper.
4. Discussion The mixtures of arsenic, antimony and bismuth with silver telluride show quasibinary character in their crystallization behaviour. A miscibility
PlO TABLE Thermal System
AgpSe-As
Ag+e-Sb
Ag++Bi
3 data for Ag#e
V (mol.%)
systems
Tliq
T Inoncl
T eut
Toha
TI
Tz
T3
(“C)
(“Cl
(“(3
(“Cl
138
-
-
-
-
498 497 494 494 496 497 -
416 415 472 473 475 414 -
538 544 -
(“Cl
WI
(“C)
(“C)
851 833 797 -
1124 1106 1070 -
-
-
716
989
741 768 783 793 793 793 793 784 -
705 707 707 708 709 709 708 708 706
9.9 20.3 27.5 42.1 55.9 64.0 72.5 18.1 82.5 90.0 95.1
821 745 673 -
1094 1018 946 -
-
-
651 650 668 668 660 650 621 580 554
560 593
833 866
-
521 521 524 526 526 522 521 525 525 526 527
1.7 17.8 32.0 41.1 49.8 58.6 13.7 80.9 90.1 95.1
828 -
1101 -
-
-
779 704 642 513 395
1052 977 915 786 668
10.4 19.3 30.0 40.0 49.5 59.7 69.8 80.2 89.9
799 198 791 803 803 -
-
262 264 264 263 264 264 265 263 260 262
137 138 135 136 122 126 125
130 124 -
736 137 740 736 733 -
133 132 133 132
130
gap in the primary crystallization region of y-Ag,Te was observed in the As-AgzTe and Bi-AgzTe cross sections. The P-7 transformation temperature of AgzTe is decreased by the addition of a Vb element whereas no detectable change in the temperature of the (Y-/I transformation could be observed. The influence of these elements increases in the order As > Sb > Bi. A different picture was found in the AgzSe-Vb cross sections. Only the AgzSe-Bi system behaves as a quasibinary and is of simple eutectic character with a miscibility gap in the liquid state. The systems AgzSe-As and AgzSe-Sb show pseudobinary behaviour in their crystallization. In the case of the AgzSe-Sb system the results indicate that the miscibility gap in
Pll TABLE Thermal System
AgaTe-As
AgzTe-Sb
AgaTe-Bi
the the and and
4 data for AgzTe
systems
V (mol.%)
7.6 14.1 23.5 28.3 37.8 47.6 60.2 72.1 82.7 87.5 95.9 96.1
Tliq
T
T mono
T eut
T,-p
To-r
CC)
(K)
(“C)
(“C)
(“Cl
(“Cl
912 886 872 852 -
-
1185 1159 1145 1125 -
793 761 790 793
1066 1034 1063 1066
841 835 835 837 833 834 834 829 -
736 740 738 736 738 737 736 736 737 734 734 731 555 553 553 554 556 556 555 554 553 555 554 554 553 553
5.0 10.0 15.0 20.0 25.0 30.0 40.0 50.0 60.0 70.0 80.0 85.0 90.0 95.0
896 861 832 817 805 788 771 759 737 711 649 612 555 590
1169 1134 1105 1090 1078 1061 1044 1032 1010 984 922 885 828 863
-
7.5 16.4 22.7 29.0 37.8 44.7 55.3 62.0 69.8 77.8 82.4 86.8 92.4
898 865 855
1171 1138 1128
831 833 833 832 836 825 826 -
-
817 799 744 709 645 576
1090 1072 1017 982 918 849
-
263
145 147 145 146 147
780 779 7 80 781 780 783 778 780 779 -
147 152 147 147 142 144 147 148 146 144 144 146 147 147 148
144 145
264 264 265
144
264 265 263 263
148 150 142
780 786 783 783 783 778
-
788 790 790 791 792 793 793 788 -
-
Sb-Se system and the miscibility gap in the Ag-Se system, existing in primary crystallization field of silver, are combining in ternary space intersecting the section Ag,Se-Sb. The experimental points at 496 “C 478 “C are ternary eutectic effects which are due to incomplete forma-
P12
tion of the equilibria between liquid and solid phases. These non-equilibrium effects were not observed in the corresponding AgzSe-As section. In the system AgaS-As we expected a large miscibility gap, but the experimental results reveal a simple eutectic behaviour. The large miscibility gaps in the Ag-As-S ternary system, which were observed by Roland on both sides of the section Ag,S-As, do not show up. The primary crystallization region of arsenic is unusually large compared with the other Ib-Vb-VIb systems (5,6]. Most of the nine cross sections presented in this paper can be understood from the topology of the constituent binary systems, which in fact reveal their similarity to the CuaVI-Vb systems. The exceptions are the AgaS-Sb and Ag,S-Bi cross sections. In these systems the ternary compounds AgBiSz, Ag,SbS, and AgSbS, with large surfaces of primary crystallization are formed, which determine the ternary space by their equilib~a between silver and, respectively, Ag,Sb and Ag,Sb. In these cases ternary crystallization effects were observed. A second reason for non-quasibinary crystallization effects in the Ag,S-Sb system is a miscibility gap which is formed by the intersection of the miscibility gap at the silver-rich side of the Ag-S system with that of the Sb-S system in the ternary space. No interpretation of the sections Ag,S-Sb and AgzS-Bi is possible because of the lack of measurements in ternary space. The systems Ag-Bi-S will be presented in a future publication. Generally, the miscibility in melts of ternary Ag-Vb-VIb systems increases parallel to the miscibility in the boundary Ag-VIb and V-VIb systems, namely from Ag-S to Ag-Te and from As-S to Bi-Te. However this tendency is not as clearly revealed by the AgzVIb-Vb cross sections as by the similar Cu,VIb-Vb [ 31 cross sections. The comparison with these latter systems shows that miscibility in the silver systems is more restricted. The higher solubilities in the copper systems may be caused by the higher melting temperature of the copper chalcogenides.
Acknowledgments The authors wish to express their gratitude der Chemie for financial support.
to the DFG and the Fond
References 1 2 3 4 5 6
B. R. B. G. B. B.
Gather and R. Blachnik, Z. Metallkd., 66 (1974) 356 - 359. Blachnik, A. Jager and G. Enninga, Z. Naturforsch., Teii B, 30 (1975) Gather and R. Blaehnik, J. Less-Common Met., 48 (1976) 205. W. Roland, Metall. Trans., 1 (1970) 1811. Gather and R. Blachnik, Z. Metallkd., 67 (1976) 223 - 227. Gather, Dissertation, T. U. Clausthal, 1976.
191 - 197.
Journal of the Less-Common Metals, 58 (1978) P7 - P12 @ Elsevier Sequoia S.A., Lausanne - Printed in the Netherlands
TEMPERATURE-COMPOSITION SECTIONS OF THE TERNARY B. GATHER
DIAGRAMS Ag-(Vb)-(VIb)
and R. BLACHNIK
Anorganische Chemie, FB 8, Gesamthochschule Siegen 21 (F.R.G.) (Received
IN THE Ag, (VIb-(Vb) SYSTEMS*
Siegen, Adolf Reichwein
Str., 5900
July 26, 1977)
Summary The T-x sections AgsVIb-Vb were determined by differential thermal analysis, X-ray and metallographic methods. Three categories of phase diagrams have been found. The first consists of quasibinary systems of eutectic type, the second has eutectic behaviour with an additional miscibility gap and in the third the systems are not quasibinary.
1. Introduction In the course of investigations [ 1, 21 in our laboratory of the thermal properties of ternary chalcogenides, the cross sections AgaVIb-Vb were determined in order to get some preliminary results on the topology of the ternary systems Ag-Vb-VIb.
2. Experimental The experimental techniques were described in an earlier publication [ 31. The purities of the elements which were used in the preparations are given in Table 1. The annealing temperatures were 250 “C! for the bismuth systems and 500 “C for the others. The mixtures were annealed for 14 d.
3. Results The T-x diagrams AgsVIb-Vb were constructed from DTA measurements and metallographic examinations of the samples and are presented in
*Vb
= As, Sb, Bi; VIb = S, Se, Te.
P8
~__
Anf,mooy -----------
-._---_z
c
(a)
Af12S
,n 10
mot “I, moi
%
MO
Ag2T@ 20
40 hirenic
60 ,n
mot
.4Q %,
As
40
20 tiny &2Te
60
80
#n mot
Ol.3
in
moi
56
20
40 Bismuth
60 tn
mof
80
81
0
%
“/.,
(cl
Fig. 1. Temperature-composition diagrams in the Ag,(VIb j(Vb) sections of the ternary Ag-(Vb)-(VIb) systems: (a) the Ag$3 systems; (b) the AgzSe systems; (c) the AgzTe systems.
P9
TABLE Purity
1 of the elements
Element
Purity
&
99.999
Se, Te, Sb, Bi S
99.995 99.5
TABLE Thermal
(%)
Source Degussa Preussag Merck
2 data for the Ag@-As
V (mol.%)
10.2 19.8 30.1 40.5 49.9 59.8 70.0 80.0 89.9
system
Tliq
T cut
To+@
Q-r
(“C)
(“0
(“C)
(W
(“0
730 675 630 -
1003 948 903 -
626 640 655 690 737
899 913 928 963 1010
614 611 608 610 610 613 613 613 613
181
583 583 582 584 581 583 582 582 583
Figs. l(a) - l(c); the relevant data from the experiments are given in Tables 2 - 4. The AgzS-As diagram includes the data of Roland [ 41, which were obtained by metallographic analysis of quenched samples. In spite of the fact that the exper~ent~ methods of the two investigations were quite different, the agreement is fairly good. All mixtures, except those of AgaSAs and AgzTe-Sb which are eutectic, have a miscibility gap in the liquid state. The crystallization in the Ag,Te-VIb systems and in the mixtures Ag,Se-Bi and AgzS-As is quasibinary; the mixtures of Ag,Se with antimony and arsenic behave as pseudobinary systems. In the case .of the AgaS-VIb mixtures with antimony and bismuth, ternary c~stallization was observed. In these latter diagrams a complete interpretation of the effects could not be given without further measurements in the ternary system; these results will be reported in a future paper.
4. Discussion The mixtures of arsenic, antimony and bismuth with silver telluride show quasibinary character in their crystallization behaviour. A miscibility
PlO TABLE Thermal System
AgpSe-As
Ag+e-Sb
Ag++Bi
3 data for Ag#e
V (mol.%)
systems
Tliq
T Inoncl
T eut
Toha
TI
Tz
T3
(“C)
(“Cl
(“(3
(“Cl
138
-
-
-
-
498 497 494 494 496 497 -
416 415 472 473 475 414 -
538 544 -
(“Cl
WI
(“C)
(“C)
851 833 797 -
1124 1106 1070 -
-
-
716
989
741 768 783 793 793 793 793 784 -
705 707 707 708 709 709 708 708 706
9.9 20.3 27.5 42.1 55.9 64.0 72.5 18.1 82.5 90.0 95.1
821 745 673 -
1094 1018 946 -
-
-
651 650 668 668 660 650 621 580 554
560 593
833 866
-
521 521 524 526 526 522 521 525 525 526 527
1.7 17.8 32.0 41.1 49.8 58.6 13.7 80.9 90.1 95.1
828 -
1101 -
-
-
779 704 642 513 395
1052 977 915 786 668
10.4 19.3 30.0 40.0 49.5 59.7 69.8 80.2 89.9
799 198 791 803 803 -
-
262 264 264 263 264 264 265 263 260 262
137 138 135 136 122 126 125
130 124 -
736 137 740 736 733 -
133 132 133 132
130
gap in the primary crystallization region of y-Ag,Te was observed in the As-AgzTe and Bi-AgzTe cross sections. The P-7 transformation temperature of AgzTe is decreased by the addition of a Vb element whereas no detectable change in the temperature of the (Y-/I transformation could be observed. The influence of these elements increases in the order As > Sb > Bi. A different picture was found in the AgzSe-Vb cross sections. Only the AgzSe-Bi system behaves as a quasibinary and is of simple eutectic character with a miscibility gap in the liquid state. The systems AgzSe-As and AgzSe-Sb show pseudobinary behaviour in their crystallization. In the case of the AgzSe-Sb system the results indicate that the miscibility gap in
Pll TABLE Thermal System
AgaTe-As
AgzTe-Sb
AgaTe-Bi
the the and and
4 data for AgzTe
systems
V (mol.%)
7.6 14.1 23.5 28.3 37.8 47.6 60.2 72.1 82.7 87.5 95.9 96.1
Tliq
T
T mono
T eut
T,-p
To-r
CC)
(K)
(“C)
(“C)
(“Cl
(“Cl
912 886 872 852 -
-
1185 1159 1145 1125 -
793 761 790 793
1066 1034 1063 1066
841 835 835 837 833 834 834 829 -
736 740 738 736 738 737 736 736 737 734 734 731 555 553 553 554 556 556 555 554 553 555 554 554 553 553
5.0 10.0 15.0 20.0 25.0 30.0 40.0 50.0 60.0 70.0 80.0 85.0 90.0 95.0
896 861 832 817 805 788 771 759 737 711 649 612 555 590
1169 1134 1105 1090 1078 1061 1044 1032 1010 984 922 885 828 863
-
7.5 16.4 22.7 29.0 37.8 44.7 55.3 62.0 69.8 77.8 82.4 86.8 92.4
898 865 855
1171 1138 1128
831 833 833 832 836 825 826 -
-
817 799 744 709 645 576
1090 1072 1017 982 918 849
-
263
145 147 145 146 147
780 779 7 80 781 780 783 778 780 779 -
147 152 147 147 142 144 147 148 146 144 144 146 147 147 148
144 145
264 264 265
144
264 265 263 263
148 150 142
780 786 783 783 783 778
-
788 790 790 791 792 793 793 788 -
-
Sb-Se system and the miscibility gap in the Ag-Se system, existing in primary crystallization field of silver, are combining in ternary space intersecting the section Ag,Se-Sb. The experimental points at 496 “C 478 “C are ternary eutectic effects which are due to incomplete forma-
P12
tion of the equilibria between liquid and solid phases. These non-equilibrium effects were not observed in the corresponding AgzSe-As section. In the system AgaS-As we expected a large miscibility gap, but the experimental results reveal a simple eutectic behaviour. The large miscibility gaps in the Ag-As-S ternary system, which were observed by Roland on both sides of the section Ag,S-As, do not show up. The primary crystallization region of arsenic is unusually large compared with the other Ib-Vb-VIb systems (5,6]. Most of the nine cross sections presented in this paper can be understood from the topology of the constituent binary systems, which in fact reveal their similarity to the CuaVI-Vb systems. The exceptions are the AgaS-Sb and Ag,S-Bi cross sections. In these systems the ternary compounds AgBiSz, Ag,SbS, and AgSbS, with large surfaces of primary crystallization are formed, which determine the ternary space by their equilib~a between silver and, respectively, Ag,Sb and Ag,Sb. In these cases ternary crystallization effects were observed. A second reason for non-quasibinary crystallization effects in the Ag,S-Sb system is a miscibility gap which is formed by the intersection of the miscibility gap at the silver-rich side of the Ag-S system with that of the Sb-S system in the ternary space. No interpretation of the sections Ag,S-Sb and AgzS-Bi is possible because of the lack of measurements in ternary space. The systems Ag-Bi-S will be presented in a future publication. Generally, the miscibility in melts of ternary Ag-Vb-VIb systems increases parallel to the miscibility in the boundary Ag-VIb and V-VIb systems, namely from Ag-S to Ag-Te and from As-S to Bi-Te. However this tendency is not as clearly revealed by the AgzVIb-Vb cross sections as by the similar Cu,VIb-Vb [ 31 cross sections. The comparison with these latter systems shows that miscibility in the silver systems is more restricted. The higher solubilities in the copper systems may be caused by the higher melting temperature of the copper chalcogenides.
Acknowledgments The authors wish to express their gratitude der Chemie for financial support.
to the DFG and the Fond
References 1 2 3 4 5 6
B. R. B. G. B. B.
Gather and R. Blachnik, Z. Metallkd., 66 (1974) 356 - 359. Blachnik, A. Jager and G. Enninga, Z. Naturforsch., Teii B, 30 (1975) Gather and R. Blaehnik, J. Less-Common Met., 48 (1976) 205. W. Roland, Metall. Trans., 1 (1970) 1811. Gather and R. Blachnik, Z. Metallkd., 67 (1976) 223 - 227. Gather, Dissertation, T. U. Clausthal, 1976.
191 - 197.