Investigation on Phase Transition and Microstructure of Pseudoboehmite by Eu^{3 +} Ion as Fluorescence Probe

Phase transition and microstructure of pseudoboehmite were investigated by Eu³⁺ ion as fluorescence probe in this paper. Eu³⁺ ion as fluorescence probe was prepared by Eu³⁺ doped pseudoboehmite Sol (γ-AlOOH:Eu) in the spray drying process. The results of TG/DSC, XRD and FETEM indicated that the pseudoboehmite phase transition experienced a phase transition process of γ-AlOOH→ γ-Al₂O₃ → -Al₂O₃ → α-Al₂O₃ from 800 °C to 1400 °C. Eu³⁺ ion as a fluorescent probe substituted entirely or partially Al³⁺ into the lattice of γ-Al₂O₃, -Al₂O₃ and α-Al₂O₃. Eu-probed xerosol sample was sintered at different temperature and fluorescence spectroscopy was performed by probe samples to obtain the Eu³⁺ ion excitation and emission spectra. The results show that the Eu³⁺ ion excitation spectra and emission spectra have a significant variation in the -Al₂O₃ → α-Al₂ O₃ phase transition process as pseudoboehmite is a precursor. It can reflect the phase transition and microstructure of pseudoboehmite. Eu³⁺ ion as a fluorescent probe can be used as one of the auxiliary methods to study the phase transition and the microstructure of pseudoboehmite.