Abstract
The phase diagram of the La-S-O system at 1073 K was established with the vacuum seal technique. Six phases exist at this temperature: La2O3 (B-type), LaS2, La2S3, La2O2SO4, La2O2S and La2O2S2. The thermodynamic functions for the reaction La2O2SO4=La2O3+SO2+1/2 O2 were determined by using the emf method at temperatures from 1123 to 1373 K. The mechanisms of the oxidation reactions in the La-S-O system under different partial pressures of oxygen (−4.4 < log\(P_{O_2 }\) <−0.7) were also investigated by means of DTA, TG and powder X-ray diffractometry.
Zusammenfassung
Das Phasendiagramm des La-S-O-Systems bei 1073 K wurde bestimmt. Bei dieser Temperatur liegen 6 Phasen vor, und zwar La2O3 (B-Typ), LaS2, La2S3, La2O2SO4, La2O2S und La2O2S2. Für die Reaktion La2O2SO4=La2O3+SO2+1/2 O2 wurden die thermodynamischen Funktionen im Temperaturbereich von 1123–1373 K nach der EMF-Methode bestimmt. DTA, TG und Pulver-Röntgendiffraktometrie wurden zur Untersuchung der Mechanismen der im La-S-O-System verlaufenden Oxydationsreaktionen herangezogen, wobei der Sauerstoffpartialdruck in den Grenzen von − 4.4 < log\(p_{O_2 }\) < <-0.7 variiert wurde.
Резюме
С помощью вакуумной и золированной техник и была установлена фаз овая диаграмма системы La-S-O п ри 1073 К. При этой темпера туре существует шесть фаз: La2O3 (Б-типа), LaS2, La2S3, La2O2SO4, La2O2S и La2O2S2. Используя метод э. д. с., были определены термодинамические п араметры реакции La2O2SO4=La2O3+ SO2+1/2 О2 в температурном интербале 1123–1373. С помощь ю ДТА, ТГ и порошковой рентгенодиффрактом етрии исследованы механиз мы реакций в системе La-S-O б области парциальных давлени й кислорода −4.4 < log\(P_{O_2 }\)< −0.7.
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Kitazawa, Y., Kunimoto, Y., Wakihara, M. et al. Phase equilibria and oxidation mechanisms in the LA-S-O system. Journal of Thermal Analysis 25, 279–290 (1982). https://doi.org/10.1007/BF01912953
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DOI: https://doi.org/10.1007/BF01912953