화학공학소재연구정보센터
Journal of the American Ceramic Society, Vol.101, No.3, 1381-1392, 2018
Determination of crystal size distributions in alumina ceramics by a novel X-ray diffraction procedure
A novel X-ray diffraction based method is presented, capable of determining volume-based crystal size distribution (CSD) of polycrystalline materials and crystalline powders with unprecedented sampling statistics; the method is named fast X-ray diffraction crystal size distribution analysis (FXD-CSD). FXD-CSD can be performed with standard laboratory X-ray diffractometers equipped with a position sensitive detector and uses a software package written in Python for the data analysis. FXD-CSD is a destruction-free and generally applicable method to establish CSDs of polycrystalline materials as well as powders for sizes well below 1m up to about 100m; it even allows for studies of samples enclosed in complex environments, e.g., for insitu measurements in a furnace or in a pressure cell. To show the capability of the method the microstructural evolution of four alumina substrates with different time-spans of sintering (4, 8, 16, and 24hour at 1600 degrees C) is investigated via FXD-CSD and SEM imaging. The corresponding CSDs and average grain sizes are determined, results obtained by FXD-CSD and the line-intersection methods are compared and clear evidence for the presence of abnormal grain growth (AGG) during sintering is shown. From three tested probability density functions (PDF) describing the CSDs a log-normal PDF fits best to the volume based CSDs; the method provides size distributions with unprecedented precision opening the way to a systematic and meaningful comparison between theoretically predicted and observed CSDs.