T-x-y diagram of the Ce-Bi-Te system

Article abstract of DOI:10.1134/S0036023609020272

The character of phase interaction in the Ce-Bi-Te ternary system has been investigated by differential thermal, X-ray diffraction, and microstructural analyses, as well as by the measurement of microhardness and density of alloys. Phase diagrams of eight

Full text of DOI:10.1134/S0036023609020272

ISSN 0036-0236, Russian Journal of Inorganic Chemistry, 2009, Vol. 54, No. 2, pp. 319–322. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © S.G. Mamedova, F.M. Sadygov, T.M. Il’yasly, Z.I. Ismailov, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 2, pp. 364–367.
PHYSICOCHEMICAL ANALYSIS
OF INORGANIC SYSTEMS
T–x–y Diagram of the Ce–Bi–Te System
S. G. Mamedova, F. M. Sadygov, T. M. Il’yasly, and Z. I. Ismailov
Rasul-zade State University, ul. Khalilova 23, Baku, 370148 Azerbaijan
Received August 14, 2007
Abstract—The character of phase interaction in the Ce–Bi–Te ternary system has been investigated by differential
thermal, X-ray diffraction, and microstructural analyses, as well as by the measurement of microhardness and den-
sity of alloys. Phase diagrams of eight polythermal and projection of the liquidus of the Ce–Bi–Te ternary system
have been constructed.
DOI: 10.1134/S0036023609020272
In this work, we present a projection of the liquidus
Investigations were performed using a conventional
surface of the Ce–Bi–Te system constructed with con- set of experimental methods of physicochemical analy-
sideration of published and our own data for the Ce–Te, sis: differential thermal analysis (DTA), involving
Ce–Bi, and Bi–Te binary systems [1–4].
high-temperature DTA; X-ray powder diffraction;
Invariant equilibria in the Ce–Bi–Te system
Point
Point
no.
Equilibrium
Ce Bi + CeTe
∼ T, ä
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
P1
L + Ce Bi
1300
1100
900
4
3
5
3
P2
L + Ce Bi
Ce Bi + CeTe
2
5
3
E1
P3
L
CeTe + Ce + Ce Bi
2
L + Ce Bi
CeBi + CeTe
1250
1100
480
4
3
P4
L + CeBi
CeBi + CeTe
2
E2
P5
L
Bi + CeBi + CeTe
2
L Bi Te
BiTe + CeTe
760
2
3
P6
L + BiTe
Bi Te + CeTe
650
2
P7
L + Bi Te
Bi Te + CeTe
550
2
14
6
1
1
1
1
1
1
1
1
1
1
E3
E4
P8
L
L
CeTe + Bi Te + Bi
500
14
6
Bi Te + Ce Te + CeTe
600
2
3
3
4
L + Ce Te
S + Bi Te
3
780
3
4
2
e13
E5
P9
L
L
Bi Te + α + S
800 (degenerate)
2
3
Bi Te + Te + CeTe
3
520
750
700
660
600
570
2
3
L + Ce Te
S + Bi Te
2 3
2
3
P10
P11
P12
P13
L + S
Ce Te + Bi Te
4 7 2 3
L + Ce Te
CeTe + Bi Te
2 2 3
4
7
L + CeTe2
Ce Te + Bi Te
2 5 2 3
L + Ce Te
CeTe + Bi Te
3 2 3
2
5
3
19

3
20
MAMEDOVA et al.
T, K
2
000
1
1
600
L
L
1
300
1
250
200
L + CeTe
+
ëeBi
1
L + CeTe + Ce Bi
5
3
100
L + Ce
L
1000
L + α
L + CeTe
L + CeTe + Ce Bi
900
L + Ce + CeTe
2
L + β + CeTe
8
4
00
00
L + α + CeTe
α
760
L+ γ + CeTe
650
CeTe + Ce Bi + Ce
2
5
50
5
20
4
70
Bi Te
20
40 CeTe + CeBi + Bi 60
80
Ce
2
3
2
Ce at %
Fig. 1. Phase diagram of the Bi Te –Ce system. Solid solutions: α on the basis of Bi Te , β on the basis of BiTe, and γ on the basis
2
3
2
3
of Bi Te.
2
microstructural analyses; and density and microhard-
ness measurements.
In the Bi Te –CeTÂ system, the Ce Bi Te ternary
2 3 4 2 7
compound is formed by a peritectoid reaction at 600 K:
α-Bi Te + CeTÂ ↔ Ce Bi Te . A CeTe-based solubility
2
3
4
2
7
The synthetic procedure was similar to that given in
region exists [8].
The Bi Te –Ce Te , Bi–CeTe, and Ce Bi –CeTe
[
5, 6].
We investigated five quasi-binary sections, namely,
Bi Te –Ce TÂ , Bi Te –CeTe, Bi Te –Ce Te , Bi–CeTe,
2
3
3
4
4
3
joins are quasi-binary sections of the Ce–Bi–Te ternary
system; their phase diagrams are simple eutectics, and
no ternary compounds are formed in them [9].
2
3
2
3
2
3
2
3
3
4
and Ce Bi –CeTe, and three non-quasi-binary sections,
4
3
Bi Te –Ce, Ce Bi –Te, and [Ce0.92Bi0.08]–Te, and con-
2
3
4
3
To determine the shape of univariant curves and the
positions of invariant points, we investigated the above-
mentioned quasi-binary joins.
structed their phase diagrams [7–9].
To synthesize the starting components and interme-
diate phases, we used Tsem-0 grade cerium and grade
B-4 bismuth and tellurium.
The Bi Te –Ce join (Fig. 1) intersects three subordi-
2
3
nate ternary systems, namely, Bi Te –Bi–CeTe, CeTe–
2
3
The character of chemical interaction in previously
studied systems is as follows.
Bi–Ce Bi , and Ce Bi –ëÂíe–Ce. In the subordinate
system, ternary eutectics crystallize along the isother-
mal sections corresponding to 520, 470, and 900 K
4
3
4
3
The Bi Te –Ce TÂ join is quasi-binary. The Ce TÂ
3
2
3
2
3
2
(
table).
ternary compound is formed in the system at 950 K and
0 mol % CeBiTe . The eutectic crystallizes at 800 K
5
The Ce Bi –Te join intersects four subordinate ter-
3
4
3
and 20 mol % Ce Te .
nary systems, namely, CeTe–Bi–Ce Bi , CeTe–Bi–
4 3
2
3
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 54 No. 2 2009

THE T–x–y DIAGRAM OF THE Ce–Bi–Te SYSTEM
321
T, K
L + e1
2
000
L
L + CeTe
1
1
600
L + δ
1
500
L + Ce Bi + CeTe
5
3
1
300
1
250
200 L + e1
L + Ce Bi + CeTe
2
1070
9
00
L
8
4
00
00
e1 + CeTe
L+ α + s
6
00
L+ CeTe + β
L+ Bi Te + CeTe
570
320
2
e1 + CeTe + CeBi
L+ Bi Te + CeTe
14
6
CeTe + β
CeTe + Bi Te + Bi14Te6
CeTe + Te + Bi Te
3
2
3
2
CeTe + Bi Te + Ce Te
2
3
3
4
e1
20
40
45
50
Te at %
55
60
80
Te
Fig. 2. Phase diagram of the e –Te system.
1
Bi Te , CeTe–Ce Te –Bi Te , and Ce Te –Bi Te – (table). The system includes 19 primary crystallization
2
3
3
4
2
3
3
4
2
3
Ce Te .
fields of separate phases; notations are presented in Fig. 3.
2
3
In the subordinate system, the liquidus surface
The primary crystallization region of the CeTe
involves the primary crystallization region of eight refractory phase is the largest in the Ce–Bi–Te ternary
phases, namely, Ce Bi , CeTe, α-(Ce Te + Ce Te ), system. It is bound by e E , P P , P e P , P P , P E ,
4
3
3
4
2
3
2
1
1
2
1
3
3
3
4
4
2
Ce Te , CeTe , Ce Te , CeTe , and Te. The DTA peaks P E , P P , P P , P e E , and e E univariant lines.
4
7
2
2
5
3
7
3
6
7
6
5
5
7
4
9
4
at 480, 500, 600, and 620 K are due to eutectic equilib-
ria (table).
The primary crystallization region of Ce Bi , the
4
3
melting point of which is 2013 K, also occupies a large
part of the concentration triangle.
The [Ce0.92Bi0.08]–Te join (Fig. 2) intersects the
Ce Bi –Ce–CeTe, Ce Bi –Bi–CeTe, and Bi Te –Te–
4
3
4
3
2
3
The third largest area is occupied by the primary
Ce Te subordinate ternary systems. The liquidus of the
2
3
crystallization region of the α-(Ce Te + Ce Te ) solid
3
4
2
3
system comprises seven primary crystallization branches
solutions.
of CeTe, α, CeBiTe , Ce Te , Ce Te , Ce, and Te.
3
2
5
4
7
Thirty-six univariant equilibrium curves were estab-
lished in the ternary system.
Figure 3 shows the liquidus surface projection for
the Ce–Bi–Te ternary system with isotherms differing
by 100 K.
In summary, the projection of the liquidus surface of
In the Ce–Bi–Te ternary system, involving binary the Ce–Bi–Te ternary system has been constructed for
subsystems, 19 invariant points are determined; of the first time. The Ce–Bi–Te system comprises six sub-
them, six are eutectic points and 13 are peritectic points ordinate ternary systems, six eutectic points, and 13 ter-
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 54 No. 2 2009

3
22
MAMEDOVA et al.
Bi
1
e5
E2
e4
1
p7
9
E3
p7
1
8
Bi Te
2
2
3
p4
p6
p4
1
7
p6
3
e13
e7
Bi14Te6
Bi Te
CeBi2
2
p8
e8
p3
E4
p5
p8
CeBi
p5
p3
BiTe
Ce Bi
4
3
Ce Te
C3Te CeTe
4
2
3
e7
Ce Bi
5
3
Bi Te
2
3
8
e13
4
11
e3
E4
p1
1
0
p10
S
9
p2
5
6
p4
p11
1
2
p12
p13
e1
e11
p12
7
E1
13
E5 16
Ce e2
e9
p9
e10
p11 p12
e12 Te
1
4
15
at %
Fig. 3. Projection of the liquidus surface of the Ce–Bi–Te ternary system. The primary crystallization fields: (1) Bi, (2) CeBi2,
(
3) CeBi, (4) Ce Bi , (5) Ce Bi , (6) Ce Bi, (7) Ce, (8) CeTe, (9) α-(Ce Te + Ce Te ), (10) CeBiTe , (11) Bi Te , (12) Ce Te ,
4 3 5 3 2 3 4 2 3 3 2 3 4 7
(
13) CeTe , (14) Ce Te , (15) CeTe , (16) Te, (17) BiTe, (18) Bi Te, and (19) Bi Te .
2
2
5
3
2
14
6
nary peritectic points. Primary crystallization fields of
9 phases have been outlined.
5. S. G. Mamedova, F. M. Sadygov, V. A. Gasymov, and
M. B. Babanly, Zh. Neorg. Khim. 48 (3), 494 (2003)
1
[Russ. J. Inorg. Chem. 48 (3), 422 (2003)].
6
. F. M. Sadygov, S. G. Mamedova, M. B. Babanly, and
T. M. Il’yasov, Zh. Neorg. Khim. 46 (8), 1382 (2001)
REFERENCES
[Russ. J. Inorg. Chem. 46 (8), 1244 (2001)].
1
. E. I. Yarembash and A. A. Eliseev, Chalcogenides of
Rare-Earth Elements (Nauka, Moscow, 1975) [in Rus-
sian].
7. F. M. Sadygov, S. G. Mamedova, L. F. Gamidova, et al.,
Proceedings of the 6th Republican Scientific Conference
on Physicochemical Analysis of Inorganic Materials
(
Baku, 2000), p. 102 [in Russian].
2
3
4
. G. Borzone, A. Borsese, A. Calabretta, and R. Ferro,
J. Less-Common Met. 58, 31 (1978).
8
. F. M. Sadygov, S. G. Mamedova, and S. G. Kulieva, Pro-
ceedings of the 5th Republican Scientific Conference on
Physicochemical Analysis of Inorganic Materials (Baku,
. T. B. Massalski, Binary Alloy Phase Diaqrams (Ameri-
can Society for Metals, Metals Park, Ohio, 1987), Vol. 1.
1
999), p. 29 [in Russian].
. N. P. Lyakishev, Binary Metal Phase Diagrams (Mashi-
nostroenie, Moscow, 1024), Vol. 1 [in Russian].
9. S. G. Mamedova, in Fundamental Sciences. Collected
Works (Baku, 2000), no. 3, p. 35 [in Russian].
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