Synthesis of Ca3Al2O6 via citric acid precursor

Ca3Al2O6 was synthesized via citric acid precursor. The effects of the molar ratio of citric acid to total metal cations concentration (CA/M) on the formation of Ca3Al2O6 were investigated. Increasing the CA/M promoted the formation of Ca3Al2O6. Single-phase and well-crystallized Ca3Al2O6 was obtained from the CA/M = 1, CA/M = 2 and CA/M = 4 precursor at temperatures 1100 °C, 1100 °C and 1000 °C, respectively. Ca4Al6O13 and Ca5Al6O14 were formed as intermediate phases. No Ca12Al14O33 or CaAl2O4 was observed. The mechanism of formation of Ca3Al2O6 was discussed. Differential thermal analysis and thermogravimetric (DTA/TG) and X-ray diffractometry (XRD) were used to characterize the precursors and the derived oxide powders.