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8ХИМИЧЕСКИЕ НАУКИ
Sadigov F. M.
Doctor of Chemistry, Professor, of General and Inorganic Chemistry,
Baku State University Ilyasly T. M.
Doctor of Chemistry, Professor, of General and Inorganic Chemistry,
Baku State University Ganbarova G. T. Phd student of General and Inorganic Chemistry
Baku State University
Ismailov Z. I.
Assent Professor of General and Inorganic Chemistry,
Baku State University
Mamedova S. H.
Assent Professor of General and Inorganic Chemistry,
Baku State University Садыгов Фуад Микаил,
доктор химических наук, профессор кафедры Общей и неорганической химии,
Бакинский Государственный Университет Ильяслы Теймур Мамед,
доктор химических наук, профессор, кафедры Общей и неорганической химии,
Бакинский Государственный Университет Ганбарова Гунел Тапдыг аспирант кафедры Общей и неорганической химии Бакинский Государственный Университет Исмаилов Закир Ислам, доцент, кафедры Общей и неорганической химии, Бакинский Государственный Университет Мамедова Саба Гусейнхан доцент, кафедры Общей и неорганической химии, Бакинский Государственный Университет
PHASE FORMATION IN THE Nd-Bi-Se TERNARY SYSTEM ФАЗООБРАЗОВАНИЕ В ТРОЙНОЙ СИСТЕМЕ Nd-Bi-Se
Summary: Phase interaction in the Nd-Bi-Se ternary system in investigated along nine internail joins by the methods of physicochemical analysis. Phase diagrams of the joins and the liquids surface projection for the ternary system are constructed. One compound,namely NdBiSe3 are found in the system.
Key words: selenide, bismuth, neodymium, phase, incongruently, compound, diagram, solid solutions.
Аннотация: Методами физико-химического анализа исследован фазовое взаимодействие в тройной системе Nd-Bi-Se по семи внутренним разрезах:. Построены фазовые диаграммы разрезов и проекция ликвидуса тройной системы. В системе найдено одно инконгруэнтно плавящее соединение состава NdBiSe3.
Ключевые слова: селенид, висмут, неодим, фаза, инконгруэнтно, соединение, диаграмма, твердый раствор.
Introduction
Studying of chemical interaction in Ln-BV-X (Ln-REE; BV-Sb,Bi;X-S,Se,Te) systems is of interesting relation to the use of rare-earth element sin commutation of B^X^1 -base termo-elements [1,2]. Phase diagrams of boundary binary systems of the ternary system under investigation are taren from [2,3] Material and methods of research We have been investigated the Nd-Bi-Se system over the entire concentration range. The starting materials for synthesis of alloys were metal neodium (NOM-O,Bi (B-4) and selenium (22-4)).
The alloys were prepared by direct fusion of the constituent elements in evacuated quartz ampules at 900-12500C (depending on the composition ) with the subsequent slow cooling in a switched-off furnace.
To achive an equilibrium state, the alloys were homogenized by annealing in evacuated quartz ampules for 2 weeks at a temperature 500-1000K lower than the solidus temperature.
Investigations were carried out rising a combinations of the methods of physicochemical analysis according to [4].
In order to investigate the chemical interaction over the entire concentration range and to establish projections of the Nd-Bi-Se ternary system, the following sections (systems) were studied: Bi2Se3-Nd2Se3, Bi2Se3-NdSe, Bi2Se3-Nd3Se4, Bi2Se3-Nd, NdSe-Bi, NdBi-NdSe, NdBi-Se.
DTA experiments were carried out on NTR-73 pyrometer; X-ray diffraction experiments ,on a D-2 PHSER diffractometr (CuKa radiation). MSA analysis
Ul
of the alloy system was carried out using metallographic microscope MIM-8.
The liquidus of the high-temperature part of the diagram was studied with the use of a VDTA -Sm temperature stabilizer liqudus and solidus points were read from the heating curves; the error of liquidus temperature determination was I5K.
Results and discussion
The Bi2Se3-Nd2Se3 section is quasi-binary [4]. The following compounds were identified: NdBiSe3 which melt incongruently and decompose at 955K L+ Nd2Se3~ NdBiSe3
The coordineetes of eutectic points are 15 and 725K .The solibiliy at Nd2Se3 in Nd2Se3 at 300K is 2 mol % (Fig. 1).
40 60 mol%
Figurl.Phase diagram for the Bi2Se3-Nd2Se3
Here we report experimental data on the joins Bi2Se3-NdSe, Bi2Se3-Nd3Se4, NdSe-NdBi and NdSe-Bi are pseudobinary of a simple eutectic type.
The method of microstructural analyses have been investigated the microscope of MIM-8.
Phase diagrams were established from the data of investigations. They were found to be quasi-binary sections of the Nd-Bi-Se ternary system and belong to the simple eutectic type. The data for the sections and presented in Table 1.
Table 1.
Chemical interaction in quasi-binary sections of the Nd-Bi-Se
Section Eutections point coordinates Solubility (at 300 K) Fig.
Bi2Se3-NdSe 30 mol % NdSe,800 K 70 mol% NdSe a
Bi2Se3-Nd3Se4 25 mol % Nd3Se4,850 K 6,0 mol % Nd3Se4 b
NdSe-NdBi 60 mol % NdSe,1800 K c
NdSe-Bi 2,0 mol % NdSe,538 K d
Join Bi2Se3-Nd is nonpseudo-binary and intersects four subordinate (secondary) ternary systems: Bi2Se3-Bi-NdSe (I), NdSe-Bi-NdBi (II) and NdSe-NdBi-Nd (III) (Fig. 3)
The part of the join within subordinate system I is charakterired by the formation of BiSe and Bi2Se3
phases at 610 and 585K respectively and by a three-pahse nonvariant equilibrium at 525K. The reactions procecding at these points are lised in Table 2. a b
c d T, K
Figur 2. Phase diagram for the Bi2Se3-NdSe (a), Bi2Se3-Nd3Se4 (b), NdSe-NdBi(c)
and NdSe-Bi (d)
The liquidus of subordinate system II includes the region of primary crystallization of compound NdSe.
In this part of the join,the peritectic reaction L + NdBi ~ NdBi2 + NdSe proceeds at 1075K and the ternary eutectic NdSe + NdBi2 + Bi crystallizes at 510K.
The liquidus of subordinate system III includes the field of primary crystallization of NdSe and Nd.
The following nonvariant processes occurin the solidus
L + NdBi ~ Nd4Bi3 + NdSe at 1275K L + Nd4Bi3 ~ NdsBi3 + NdSe at 1125K L + NdsBi3 ~ Nd2Bi + NdSe at 1015K
The solubility at neodyum in Bi2Se3 is ~30 mol % at 300K and ~6,0 mol % at 825K.
The liquidus surface projection of the Nd-Bi-Se system (Fig. 4) is constructed from the literature data on binary systems and the result of investigation of 5 psendo-binary and 2 nonpseudo-binary joins.
The Nd-Bi-Se systems is triangulated into eight secondary ternary systems.
NdBi-Nd-NdSe, NdBi-Bi-NdSe, Bi2Se3-Bi-NdSe, Bi2Se3-NdSe- Nd3Bi4, Bi2Se3- Nd3Bi4-Nd2Se3 and Bi2Se3-Se- Nd2Se3
T,K 2200
2000
mo1.%Nd
Figur 3. Phase diagram for the Bi2Se3-Nd
Eighteen fields of primary crystallization are drawn internary system of there fields correspond to the primary crystallization of the terminal components and their surface is diminished in series Bi-Nd-Se. The most extensive region in the diagram is the field of the NdSe phase (~55 mol %) and the least extensive one is the field of Se. The are nonvariant equilibria in the Nd-Bi-Se system of these E1-E2 are ternary eutectic points.
Chemical reactions that proceed at these equilibrium nonvariant points are listed in Table 2.
From the comparison of investigations of ternary systems Ln-BV-Se (Ln - Sm, Tm, Ho; BV - Sb, Bi) [58] An inference can be made that ternary compounds of compositions LnBVSe3 are formade in all systems. LnSe phase has the most extensive crystallization fieldin the systems (>50 mol %)
Figur 4. Liguides surface projection of the Nd-Bi-Se ternary system; (1) NdBi2, (2) NdBi,(3)Nd4Sb3, (4) Nd5Sb3,(5)Nd2Bi,(6) Nd,(7) NdSe,(8) Bi,(9)Bi2Se ,(10)BiSe,(11) Bi2Se3 (12) a(NdsBi4+ Nd2Se3), (13) S(NdBiSe3), (14) Nd4Se7, (15)NdSei9 (16) Nd3Se7 (17) Se (18) (19) lamination (tabaqahm)
Table 2.
Temperature and reactions for nonvariant points of the Nd-Bi-Se
Notation Reactions Temperature ,K
Ei M~Nd+Nd2Bi+NdSe 650
E2 M^Bi+NdBÎ2+NdSe 525
Ез Bi2Se3+NdSe+Bi 510
E4 Bi2Se3+NdSe++ Nd3Se4 650
e9 Bi2Se3+S 815
E5 M~Se+ Bi2Se3+ Nd3Se7 degenerate
Pi M+NdBi^NdBi2+NdSe 1075
P2 M+NdBi^Nd4Bi3+NdSe 1275
Рз M+ Nd4Bi3~NdSe+ Nd5Se3 1125
P4 M+ Nd5Se3^Nd2Se+NdSe 1065
P5 M+Nd2Se3^ Nd4Se7+a 645
Рб M+ Nd4Bi7^NdSe2+ Bi2Se3 610
P7 M+ NdSe2~Nd3Se7+ Bi2Se3 550
P8 M+ Bi2Se3^BiSe+NdSe 620
P9 M+BiSe^ Bi2Se+NdSe 585
Pi0 M+ Nd2Se3^S+a 700
Conclusion
At the result of research was investigated the chemical interaction over the entire concentration range and to establish projections of the Nd-Bi-Se ternary system, the following sections (systems) were studied:
Bi2Se3-Nd2Se3, Bi2Se3-NdSe, Bi2Se3-Nd3Se4, Bi2Se3-Nd, NdSe-Bi, NdBi-NdSe, NdBi-Se. The Bi2Se3-Nd2Se3 section is quasi-binary. NdBiSe3 was identified, which melt incongruently and decompose at 955K. The coordineetes of eutectic points are 15 and 725K.
Bi2Se3-Nd is nonpseudo-binary and intersects four subordinate (secondary) ternary systems: Bi2Se3-Bi-NdSe (I), NdSe-Bi-NdBi (II) and NdSe-NdBi-Nd (III). The Nd-Bi-Se systems is triangulated into eight secondary ternary systems. NdBi-Nd-NdSe, NdBi-Bi-NdSe, Bi2Se3-Bi-NdSe, Bi2Se3-NdSe- Nd3Bi4, Bi2Se3-Nd3Bi4-Nd2Se3 and Bi2Se3-Se- Nd2Se3.
References
1.Goltsman .B.M,Kudinov ,V.A. and Smirnov i.A.,Poluprovodnikovye thermoelectricheskie materi-aly na osnove Bi2Te3(Semiconducting Thermoelectric materials Based on Bi2Te3).Moscow :Nauka,1972
2.Abrikasov N.Kh,Bankina V.F,Poretskaya L.V et at. Poluprovodnikovye Khalkogenidy isplayy na ikh ocnove(Chalcogenide Semiconductors and Their alloys) Moscow :Nauka,1975
3.Yarembash.E.I and Eliseev A.A. Khalkogenidy redkoremelinyku metallov(Rare-Earth Chalcogenides) Moscow :Nauka,1975
4.Sadigov F.M.Ilyasly T.M. Ganbarova G.T.,Mamedova S.G.Uspexi sovremennoqo estestvoz-nanie 2016 No4,p 53-56
5. Sadigov F.M.Ilyasly T.M.Nasibova L.E ,Zh.Neorg. Chem. 2013, v 58 No 9 p 1253-1259
6. Nasibova L.E, Sadigov F.M.Ilyasly T.M. (Material konf) FAGRAN -2010 Voronej 2010,p 504-506
7. Ilyasly T.M. ,Sadigov F.M. Izv.Akad.Nauk SSSR,Neorg.Mater.1990 V 26,No 11 p 2276-2279.
8. Sadigov F.M.,Djafarova Y.K,Eynullayev A.V,Izv Neorg.Chem.2002 Vol 27,No 12 ,p 20522056.
