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AZERBAIJAN CHEMICAL JOURNAL № 1 2019
UDC 546(56.815.681.22)
INTERACTION IN THE SYSTEM CuGaS2-PbGa2S4 1S.K.Jahangirova, 2Sh.H.Mammadov, 3G.R.Gurbanov, 2O.M.Aliyev
Azerbaijan State Pedagogical University
2
Academician M.Nagiyev Institute of Catalysis and Inorganic Chemistry of NAS of Azerbaijan
3Azerbaijan State Oil and Industry University
azxim@mail.ru
Received 21.05.2018
The interaction in the system CuGaS2-PbGa2S4 which is the internal section of quasi ternary system Cu2S-Ga2S3-PbS has been studied for the first time using the methods of differential-thermal, X-ray phase and microstructural analyses and measurement of microhardness and T-x state diagram has been plotted. It was established that the section CuGaS2-PbGa2S4 belongs to a simple eutectic type with coordinates of eutectic point: 60 mol% PbGa2S4 and 7=1015 K. The formation of narrow regions of solid solutions was established on the basis of components.
Keywords: interaction, system, eutectic, solid solution, X-ray analysis.
https://doi.org/10.32737/0005-2531-2019-1-46-49
Introduction
It is known that ternary sulphides CuGaS2 and PbGa2S4 exhibit unique physical properties (photosensitivity, induced approximate photoef-fects, photoelectric memory, luminescence and other) [1-4], which also have an applied value in various fields of electronics and before first of all for photoelectronics.
In the system PbS-Ga2S3 [5, 6] compounds PbGa2S4 and Pb2Ga2S5 are formed. According to [5] both compounds are formed by peritetic reaction and melt with decomposition at 1203 and 1173 K, correspondingly. Unlike [5], in the work [6] it was established that PbGa2S4 and Pb2Ga2S5 melt congruently at 1163 and 1033 K, correspondingly, and the whole system PbS-Ga2S3 acts like the systems Cu2S-Ga2S3 [7] and SrS-Ga2S3 [8]. According to [2], PbGa2S4 is a phase of a variable composition. Compound PbGa2S4 belongs to structural type of EuGa2S4 and is crystallized in rhombic syn-gony (a=20.44, b=20.64, c=12.09 A. Space group - Fddd, z=32. p=4.94 g/cm3 [5].
According to [9] CuGaS2 melts congruently at higher than 1548 K, belongs to structural type of chalcopyrite and is crystallized in tetragonal syngony with lattice parameters of a=5.349, c=10.470 A. CuGaS2 is a ^-type semiconductor with band-gap energy of AE=2.38 eV.
The present work is aimed at studying the interaction in the system CuGaS2-PbGa2S4 and plotting T-x state diagram.
Experimental part
We studied the system CuGaS2-PbGa2S4 to detect the character of chemical interaction between tiogallates of copper and lead, as well as to establish the existence of the regions of compounds and phases of variable composition. In the experimental part of the work we used the methods of differential-thermal (DTA), X-ray phase, microstructural analyses and measurement of microhardness. DTA was performed on thermoanalyzer NTR-70 in a temperature range of 298-1400 K. Heating rate is 10 grad/min. Aluminium oxide was used as standard. Diffractograms were taken on D2 Phaser (CuKa-radiation, Ni-filter). Microstructure analysis was performed on microscope PMT-3 at loads selected from the measurement of each phase. Density was determined using picnome-ter method. 17 alloys of different composition were synthesized for this system (Table 1).
Results and discussion
Samples were synthesized from ternary sulphides by alloying in 10-3MPa quartz ampoules sealed and preliminarily pumped of ftill residual pressure at 1200-1400 K for 8 hours with the rate of 10-15 grad/min. After the reaction we performed homogenizing annealing for 20 days at 900-950 K depending on the composition. According to thermal analysis we observed two thermal effects belonging to liquidus and solidus of the system.
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INTERACTION IN THE SYSTEM CuGaSï-PbGaïS.
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Table 1. Results of thermal, microstructure analyses, measurements of microhardness and determination of density of alloys of the system CuGaS2-PbGa2S4_
Composition, mol% Thermal heating effects, K Phase composition
CuGaS2 PbGa2S4 solidus liquidus
100 - 1548 single-phase
97 3.0 1475 1510 a(single-phase)
95 5.0 1420 a(single-phase)
90 10 1320 1430 a+p
80 20 1130 1330 a+p
70 30 1010 1240 a+p
60 40 1015 1150 a+p
50 50 1015 1070 a+p
45 55 1015 1035 a+p
40 60 1015 - eutectic
35 65 1015 1030 a+p
30 70 1015 1040 a+p
25 75 1015 1060 a+p
20 80 - 1080 a+p
15 85 1030 1100 a(single-phase)
10 90 1070 1120 a
5.0 95 1110 1140 a
3.0 97 1130 1150 a
0.0 100 1163 single-phase
mol % ^
Fig. 1. Phase diagram of the section CuGaS2-PbGa2S4.
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S.K.JAHANGIROVA et al.
State diagram of the system CuGaS2-PbGa2S4 plotted according to physico-chemical analyses is shown in Figure 1.
Microstructure analysis of annealed alloys (diluted solution of nitric acid was used as an etching agent) showed that alloys comprising 0-7 and 83-100 mol % PbGa2S4 are singlephase, but the rest alloys are double-phase.
Results of X-ray phase analysis are consistent with the data of microstructure analysis and confirm the formation of a narrow field of solid solutions in the system based on primary ternary sulphides (Figure 2).
Table 2 shows crystal lattice parameters and some physico-chemical properties of solid solutions based on the compound PbGa2S4.
As figure shows the system CuGaS2-PbGa2S4 is quasi-binary section of quasi-ternary system Cu2S-Ga2S3-PbS and belongs to eutectic type. Eutectic point has a composition of 60
mol% PbGa2S4 and melts at 1015 K. According to the data of microstructure and X-ray phase analyses solid solution range based on tiogallate of copper CuGaS2 reaches 29 mol% of PbGa2S4 at eutectic temperature, but at 500 K - 7 mol% of PbGa2S4. Crystal lattice parameters of these solutions vary in the range of: o=5.349-5.362, c=10.470-10.49Â. Solid solution range based on PbGa2S4 reaches 20 mol% of CuGaS2 at eutectic temperature, but at 500 K - 17 mol% of CuGaS2.
As Table 2 shows, at a higher content of copper tiogallate the parameters of rhombic lattice of solid solution range based on PbGa2S4 increases.
It was established that mutual cation substitution Cu+ (rCu+ = 0.98 Â, rpb 2+ = 1.06 Â) in solid solutions (PbGa2S4)1-x(CuGaS2)x is regulated by proximity of ionic radii, coordination number of cations and character of a chemical bond.
Table 2. Results of X-ray phase analysis of the system (PbGa2S4)1-x (CuGaS2)x
Composition Lattice parameters, Â V, Â3 Z d, g/cm3 #ц, kg/mm2
а в с
х=0.0 20.44 20.64 12.09 5100.5 32 4.94 275
х=0.02 20.44 20.65 12.10 5107.2 32 4.90 284
х=0.04 20.448 20.66 12.14 5128.6 32 4.87 296
х=0.08 20.460 20.665 12.158 5140.4 32 4.80 312
х=0.10 20.466 20.674 12.164 5146.7 32 4.76 317
х=0.12 20.470 20.680 12.166 5150.1 32 4.75 320
х=0.15 20.479 20.685 12.174 5154.7 32 4.50 325
х=0.17 20.484 20.700 12.180 5164.5 32 4.46 330
х=1 5.349 10.470 299.5 4 4.29 440
ty
Й
e
[ _ ..... Jji.../
i__il n \ Л „ . » . .3
1____„ ,. J» 1 A 1 .. i 2
...... К . -La..!
Fig. 2. Diffractogram of CuGaS2-PbGa2S4 system alloys: 1 - CuGaS2, 2 - 17 mol % CuGaS2, 3 - 10 mol % CuGaS2, 4 - PbGa2S4.
10 15 20 25 30 35 40 45 50 55 60 65
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INTERACTION IN THE SYSTEM CuGaS,-PbGa,S4
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Thus, we have plotted 7- xstate diagram of the system CuGaS2-PbGa2S4 for the first time. It was established that section CuGaS2-PbGa2S4 is quasi-binary and belongs to eutectic type.
Conclusion
1. State diagram of section CuGaS2-PbGa2S4 in a wide range of concentrations was plotted for the first time and it was detected that it is quasi-binary section of quasi-ternary system Cu2S-Ga2S3-PbS.
2. It was found that section CuGaS2-PbGa2S4 is eutectic type; coordinates of eutectic point correspond to 60 mol% of PbGa2S4 and 1015 K.
3. Solid solution ranges in the system CuGaS2-PbGa2S4 were determined. Solid solutions based on CuGaS2 are formed at room temperature (300 K) up to 7 mol%, but on the basis of PbGa2S4 up to 17 mol%.
4. Solid solutions based on CuGaS2 are crystallized in tetragonal syngony, solid solutions based on PbGa2S4 are crystallized in rhombic syngony.
References
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2. Asatryan G.R., Badikov V.V., Kramush Chenko D.D., Khramtsov V.A. Electron Paramagnetic resonance of Dy3+ ions lead thiogallate single crystals
// Phys. Solid State. 2012. V. 54. No 6. P. 12451248.
3. Wagner S., Shay J.L., Tell B., Kasper H.M. Green electroluminescence from CdS-CuGaS2 hetero-diodes // Appl. Phys. Letters. 1973. V. 22. No 8. P. 351-353.
4. Abrahams S.G., Bernstein J.L. Piezoelectric nonlinear optic CuGaS2 and CuInS2 crystal structure: sublattice distortion in A'S'^CY1 type chalcopy-
rites // J. Chem. Phys. 1973. V. 59. No 10. P. 5415-5422.
5. Par A. Chilonet. Mazurier A., Guittard M.Systeme Ga2S3-PbS, diagrames de phase, etude crystal-lographique // Mater. Res. Bull. 1979. V. 14. P. 1119-1124.
6. Badikoia D., Badikov V., Doroshenko M., Fin-tisova A., Shavyrdiaeva G. Novyi nizkofononnyi kristall tiogallata svintca v kachestve matritcy dlia lazerov srednego IK-diapazona // Fotonika. 2008. № 4. S. 24-27.
7. Komatsu C., Hidaka C., Takizawa T. Phase diagram of the CaS-Ga2S3 system and molt growth of CaGa2S4 single crystals // J. Crystal Growth. 2001. V. 222. P. 574-580.
8. Komatsu C., Takizawa T. Phase diagram of the SrS-Ga2S3 system and its applications to the single crystals growth of SrGa2S4 // J. Crystal Growth. 2000. V. 210. P. 677-680.
9. Goriunova N.A. Novye poluprovodnikovye ma-terialy elektronnoi tekhniki. V kn: Novye polu-provodnikovye pribory. Himiia, fizika, tekhnika. M. 1971. S. 3-12.
10. Ringeissen J., Reqolini J.L., Lewonczuk S. Optical properties of CuGaS2 // Surface Sci. 1993. V. 37. No 3. P. 777-785.
CuGaS2-PbGa2S4 SISTEMINDO QAR§ILIQLI TOSIR
S.K.Cahangirova, §.H.Mammadov, H.R.Qurbanov, O.M.Oliyev
Differensial termiki, rentgen faza, mikroqurulu§ analizlari va mikrobarkliyin olgulmasi ila ilk dafa Cu2S-Ga2S3-PbS kvaziuglu sisteminin daxili kasiyi olan CuGaS2-PbGa2S4 sistemi tadqiq olunmu§ va sistemin T-x hal diaqrammi qurulmu§dur. Muayyan olunmu§dur ki, CuGaS2-PbGa2S4 sistemi evtektik tipli olub, evtektika noqtasinin koordinatlan 60 mol% PbGa2S4 va T=1050 K-dir. ilkin komponentlarin asasinda mahdud hallolma sahasi oldugu muayyan edilmi§dir.
Acar sozbri: qar§iliqli tasir, sistem, evtektika, bark mahlul, rentgenfaza analizi.
ВЗАИМОДЕЙСТВИЕ В СИСТЕМЕ CuGaS2-PbGa2S4
С.К.Джахангирова, Ш.Г.Мамедов, Г.Р.Курбанов, О.М.Алиев
Методами дифференицально-термического, рентгенофазового и микроструктурного анализов, а также измерением микротвердости впервые изучено взаимодействие в системе CuGaS2-PbGa2S4, являющейся внутренним разрезом квазитройной системы Cu2S-Ga2S3-PbS, и построена Т-х-диаграмма состояния. Установлено, что разрез CuGaS2-PbGa2S4 относится к простому эвтектическому типу с координатами эвтектической точки: 60 мол.% PbGa2S4 и Т=1015 К. На основе компонентов установлено образование узких областей твердых растворов.
Ключевые слова: взаимодействие, система, эвтектика, твердый раствор, рентгенфазовый анализ.
AZORBAYCAN KIMYA JURNALI № 1 2019
