Specific signatures of α-alumina powders prepared by calcination of boehmite or gibbsite

The specific signatures of α-Al2O3 powders by a combination of X-ray diffraction (Rietveld analysis), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, thermal analysis (TG–DTA) and cathodoluminescence (CL) were investigated. Thus, α-alumina was prepared by calcination of boehmite or gibbsite at 1573 K for 24 h. The size of α-alumina crystallites obtained using boehmite precursor was smaller than that obtained using gibbsite precursor. The difference in oxygen vacancies (F+-centers) amount between α-Al2O3 powder obtained by calcination of gibbsite and boehmite was confirmed by CL spectra. Furthermore, the Ti3+ emission at 1.71 eV is absent in α-Al2O3 powder obtained by calcination of gibbsite. CL has been demonstrated as a possible method for differentiation between the various α-alumina powders.