Abstract
A method of calculation of average heat capacities of phase transformation products of complex oxides is suggested. The method takes into account the physical state of products and the increase in the heat capacities of products due to the change of entropy at a phase transformation.
Average heat capacities of products formed in a congruous melting of compounds (YCuO2 and Y4Ba3O9), in an incongruous melting of compounds (Y2Cu2O5, BaCuO2, BaCu2O2, Y2BaCuO5, YBa2Cu3O7, YBa2Cu3O6) and in a decomposition in a crystalline state of compounds (Y2BaO4, Y2Ba2O5, Y2Ba4O7, Ba2CuO3, Ba3Cu5O8, YBa2Cu3.5O7.5, YBa2Cu4O8, YBa2Cu5O9) was estimated by using three methods.
Zusammenfassung
Es wird eine Methode zur Berechnung von mittleren Wärmekapazitäten der Phasenumwandlungsprodukte von Komplexoxiden vorgeschlagen. Diese Methode berücksichtigt den physikalischen Zustand der Produkte und das wegen der Entropieänderung während der Phasenumwandlung eintretende Ansteigen der Wärmekapazitäten der Produkte.
Mittels drei Methoden wurden die mittleren Wärmekapazitäten von Produkten geschätzt, die bei einem kongruenten Schmelzen der Verbindungen YCuO2 und Y4Ba3O9, bei einem inkongruenten Schmelzen der Verbindungen Y2Cu2O5, BaCuO2, BaCu2O2, Y2BaCuO5, YBa2Cu3O7, YBa2Cu3O6 und bei der Zersetzung im kristallinen Zustand der Verbindungen Y2BaO4, Y2O5, Y2Ba4O7, Ba2CuO3, Ba3Cu5O8, YBa2Cu3.5O7.5, YBa2Cu4O8, YBa2Cu5O9 entstanden.
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Moiseev, G., Vatolin, N., Štępánek, B. et al. Estimation of average heat capacities of condensed phase transformation products in the Y−Ba−Cu−O system. Journal of Thermal Analysis 43, 469–476 (1995). https://doi.org/10.1007/BF02546835
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DOI: https://doi.org/10.1007/BF02546835