Сибирский федеральный университет

Тип публикации: статья из журнала

Год издания: 2022

Идентификатор DOI: 10.1016/j.jssc.2022.123438

Ключевые слова: melting enthalpy, neodymium oxysulfide, neodymium sulfide, optical bandgap, phase diagram, structure

Аннотация: We have determined the thermal characteristics and optical properties of the sulfide and oxysulfide phases in the Nd2S3 - Nd2O3 system. A congruent melting peak at temperature 1801 ​± ​4.9 ​°C with ΔH ​= ​65.2 ​± ​6.7 ​kJ/mol was detected for the Nd2S3 compound by the DSC method. The characteristics of the α-Nd2S3 → γ-Nd2S3 polymorphic transition are t ​= ​1183 ​± ​1.8°С, and ΔH ​= ​7.5 ​± ​0.3 ​kJ/mol. The γ-Nd2S3 phase obtained upon cooling during annealing at 800 ​°C is retained for up to 30 ​h, and then the γ-Nd2S3 → α-Nd2S3 transition occurs within 20 ​h. The microhardness of the phases is: α-Nd2S3 H ​= ​451 ​± ​4 HV; γ-Nd2S3 H ​= ​531 ​± ​4 HV. It was found by the TG method that the Nd10S14O phase thermally dissociates at temperatures above 1400 ​°C. The mass loss is 0.5 mass % at 1580 ​°C and 1.0 mass % at 1620 ​°C, but the samples remain single-phase ones after cooling. However, two impurity phases γ-Nd2S3-X and Nd2O2S appear in the Nd10S14O samples treated at temperatures above 1620 ​± ​20 ​°C. For samples of the Nd10S14O phase annealed in an argon atmosphere at temperatures of 1050, 1400, 1580 ​°C, a regular decrease in the unit cell parameters and optical band gap was recorded: 1050 ​°C a ​= ​15.06291(28), c ​= ​19.97864(35), Eg ​= ​2, 63 ​eV, 1400 ​°C a ​= ​15.04779(36), c ​= ​19.97160(44), Eg ​= ​2.64 ​eV; 1580 ​°C a ​= ​15.03532(48), c ​= ​19.94984(60), Eg ​= ​2.51 ​eV. The microhardness of Nd10S14O is H ​= ​549 ​± ​10 HV. The Nd2O2S phase has H ​= ​593 ​± ​4 HV, Eg ​= ​4.28 ​eV. The phase diagram of the Nd2S3 - Nd2O3 system from 1000 ​°C to the melt was constructed. The Nd2O2S phase melts congruently at 2050 ​± ​30 ​°C. Eutectics with coordinates 23 ​mol. % Nd2O3 (0.3484 Nd10S14O ​+ ​0.6516 Nd2O2S), t ​= ​1553 ​± ​1.8°С ΔH ​= ​187 ​± ​19 ​J/g; 82 ​mol. % Nd2O3; (0.54 Nd2O2S ​+ ​0.46 Nd2O3), t ​= ​1970 ​± ​30°С were obtained. The liquidus of the Nd2S3 - Nd2O3 system was built according to DSC data and calculated using the Redlich-Kister equation. The melting enthalpy of Nd2O2S ΔH ​= ​67 ​kJ/mol was calculated using the Schroeder equation. © 2022 Elsevier Inc.

Журнал: Journal of Solid State Chemistry

Выпуск журнала: Vol. 314

Номера страниц: 123438

ISSN журнала: 00224596

Издатель: Academic Press Inc.

• Osseni S.А. (Kaba Chemistry and Applications Research Laboratory, Faculty of Sciences and Technologies of Natitingou/ National University of Science, Technology, Engineering and Mathematics (UNSTIM), Abomey, BP: 2282, Benin, Institute of Chemistry, Tyumen State University, Tyumen, Volodarsky str. 6625003, Russian Federation)
• Andreev P.O. (Institute of Chemistry, Tyumen State University, Tyumen, Volodarsky str. 6625003, Russian Federation)
• Polkovnikov A.A. (Institute of Chemistry, Tyumen State University, Tyumen, Volodarsky str. 6625003, Russian Federation)
• Zakharov B.A. (Boreskov Institute of Catalysis SB RAS, Novosibirsk, Lavrentiev Ave. 5630090, Russian Federation, Novosibirsk State University, Novosibirsk, Pirogova str. 2630090, Russian Federation)
• Aleksandrovsky A.S. (Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, Akademgorodok str. 50, building 38660036, Russian Federation, Siberian Federal University, Krasnoyarsk, Svobodnyj av. 79660079, Russian Federation)
• Abulkhaev M.U. (Institute of Chemistry, Tyumen State University, Tyumen, Volodarsky str. 6625003, Russian Federation)
• Volkova S.S. (Institute of Chemistry, Tyumen State University, Tyumen, Volodarsky str. 6625003, Russian Federation)
• Kamaev D.N. (Institute of Natural Sciences and Mathematics, Kurgan state University, Kurgan, Sovetskaya str. 2, b. 4640020, Russian Federation)
• Kovenskiy I.M. (Tyumen Industrial University, Tyumen, Volodarsky str 38625000, Russian Federation)
• Nesterova N.V. (Institute of Chemistry, Tyumen State University, Tyumen, Volodarsky str. 6625003, Russian Federation)
• Kudomanov M.V. (Tyumen Industrial University, Tyumen, Volodarsky str 38625000, Russian Federation)
• Andreev O.V. (Institute of Chemistry, Tyumen State University, Tyumen, Volodarsky str. 6625003, Russian Federation, Institute of Solid State Chemistry, Ural Branch, Russian Academy of Sciences, Yekaterinburg, Pervomaiskaya str. 91620990, Russian Federation)

• Scopus