Formation mechanisms of Wuboraite (CaAl2Cr2O7) in air and Ar atmosphere

摘要

Recently, a new high-temperature ternary Cr(III) phase (Wuboraite, CaAl2Cr2IIIO7) was synthesized in the Al2O3-CaO-Cr2O3 system. However, its formation & chemical transformation mechanism is yet to be explored in detail. And here, we investigated the system between 500 and 1600 degrees C under the air and argon (Ar) atmosphere via solid-state reaction using XRD, TG-DSC, XPS, and leaching tests. Wuboraite formation starts at different temperatures (-1500 &-1100 degrees C) under different atmospheres (air and Ar). The intermediate compounds, CaCrVIO4 and CaCr2IIIO4, formed under air and Ar atmospheres, play a crucial role in wuboraite conversion given proper temperature and stoichiometry.

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