Determination of crystallite size and strain values by fourier method for α- Al2O3

Abstract

The sintering of Al(OH)3 powder for 2 hours each run in the temperature range 1673 K to 1873 K gives rise to the following crvstallization sequence:

γ- Al₂O₃ → γ-θ -Al₂O₃ → θ+α- Al₂O₃ → α- Al₂O₃

The crvstallographic structures of the above products are assessed by x-ray diffraction method . The variation of crystallite size and root mean square (rms) strains in a- Al03 powder with sintering the temperature range 1673 K to 1873 K are studied by applying Fourier method using Mitra  &Misra technique for 3 crystallographic reflections (104), (113) and (116). The results show that the lower temperature α- Al₂O₃ (1673 K) derived from Al(OH)₃ produces lower crystallite size and higher rms strain .

On the other hand, rms strain decreases with increasing the temperature to 1873K and the differences between the broadening of above reflections are decreased. Thus, the anisotropy higher temperature of sintering (1873K).Lower temperature sintering is reduced at1673 K of AI(OH)3 yield α- Al₂O₃ compacts of higher value of micro hardness number 884 and this value drops to 731 at 1873 K.