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Mechano‐Chemical Changes of Nano Sized α‐Al 2 O 3 During Wet Dispersion in Stirred Ball Mills
Author(s) -
Stenger Frank,
Götzinger Martin,
Jakob Peter,
Peukert Wolfgang
Publication year - 2004
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.200400902
Subject(s) - ball mill , fourier transform infrared spectroscopy , dispersion (optics) , thermogravimetry , materials science , scanning electron microscope , analytical chemistry (journal) , differential scanning calorimetry , transmission electron microscopy , calorimetry , phase (matter) , chemical engineering , chemistry , composite material , nanotechnology , inorganic chemistry , organic chemistry , thermodynamics , optics , physics , engineering
The mechano‐chemical changes in synthetic α‐Al 2 O 3 during wet dispersion in a stirred ball mill, are studied. It is shown that a second phase is generated which can be identified as an aluminum hydroxide (Bayerite) by use of dynamic scanning calorimetry (DSC), X‐ray diffraction (XRD), thermogravimetry (TG), Fourier transformed infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). The amount of the Bayerite phase produced increases with milling time. A comparison of the evaluated amounts from TG‐ and DSC‐measurements are in reasonable agreement. Furthermore, the measured BET surface area shows a strong dependence on the temperature of sample preparation. Depending on the temperature, the bayerite phase is seen to convert to the α‐phase again and also forms meso‐ and possibly micro‐pores, leading to a high BET surface area. In this paper, we highlight the necessity for using different methods to characterize the dispersion process, and for a correct interpretation of the measurement results.