On the Existence of Ternary Compounds in the CaO-BaO-Al2O3 System

Abstract

In this article in order to verify the probability of the formation of the compound CaBaAl4O8, a thermodynamic analysis of the following possible solid-phase reactions of its formation was carried out: formation of CaBaAl4O8 from the initial components - calcium carbon dioxide, barium carbon dioxide and aluminum oxide; the probability of formation of dual compounds CaAl2O4 and BaAl2O4 from the same raw materials (since the compound CaBaAl4O8 is located on the BaAl2O4-CaAl2O4 conjugate) and the possibility of formation of the compound CaBaAl4O8 from binary compounds CaAl2O4 and BaAl2O4. As a result of our experimental studies, the existence of ternary compounds Вa3CaAl2O7 and ВaCa2Al8O15 was confirmed, and it was found that the Вa3CaAl2O7 compound exists in the system at least up to a temperature of 1400 °C. Thus, our studies have determined an increase in the temperature limits of its existence, in contrast to the data of previous researchers, who indicated 1250 °C as the upper temperature of existence of Вa3CaAl2O7.