Electron Beam-Induced "Nanocalcination" of Boehmite Nanostrips to Mesoporous α-Alumina Phase

Phase transformation of boehmite (AlOOH) nanostrips to α-Al₂O₃ nanolaces was investigated under electron beam irradiation of a 200 keV transmission electron microscope (TEM). X-ray diffraction pattern showed that the powder consisted of boehmite phase before the electron exposure, while selected area electron diffraction patterns demonstrated the formation of stable α-alumina phase after bombardment with high-energy electrons. The in situ TEM observations revealed that the initial morphology remained unchanged while a lace-like mesostructure of α-alumina was developed.