Properties of Oxysulfide Phases and Phase Diagram of the Nd2S3–Nd2O3 System Full article
| Journal |
Journal of Solid State Chemistry
ISSN: 0022-4596 , E-ISSN: 1095-726X |
||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Output data | Year: 2022, Volume: 314, Article number : 123438, Pages count : 12 DOI: 10.1016/j.jssc.2022.123438 | ||||||||||||||||||
| Tags | Melting enthalpy; Neodymium oxysulfide; Neodymium sulfide; Optical bandgap; Phase diagram; Structure | ||||||||||||||||||
| Authors |
|
||||||||||||||||||
| Affiliations |
|
Funding (1)
| 1 | Правительство Тюменской области |
Abstract:
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.
Cite:
Osseni S.А.
, Andreev P.O.
, Polkovnikov A.A.
, Zakharov B.A.
, Aleksandrovsky A.S.
, Abulkhaev M.U.
, Volkova S.S.
, Kamaev D.N.
, Kovenskiy I.M.
, Nesterova N.V.
, Kudomanov M.V.
, Andreev O.V.
Properties of Oxysulfide Phases and Phase Diagram of the Nd2S3–Nd2O3 System
Journal of Solid State Chemistry. 2022. V.314. 123438 :1-12. DOI: 10.1016/j.jssc.2022.123438 WOS Scopus РИНЦ AN OpenAlex
Properties of Oxysulfide Phases and Phase Diagram of the Nd2S3–Nd2O3 System
Journal of Solid State Chemistry. 2022. V.314. 123438 :1-12. DOI: 10.1016/j.jssc.2022.123438 WOS Scopus РИНЦ AN OpenAlex
Dates:
| Submitted: | May 6, 2022 |
| Accepted: | Jul 18, 2022 |
| Published online: | Jul 21, 2022 |
| Published print: | Oct 1, 2022 |
Identifiers:
| Web of science: | WOS:000856570900011 |
| Scopus: | 2-s2.0-85135504536 |
| Elibrary: | 50499755 |
| Chemical Abstracts: | 2022:2063462 |
| OpenAlex: | W4286509647 |