Phenomenology and modeling of Y2O3 porous grain sintering

Yttrium oxide has promising characteristics such as chemical stability and a porous structure for various high-temperature applications in catalysis and chemical engineering. The prediction of the structural properties of Y2O3 presents a computational challenge. In this study, we implemented a phase-field approach to obtain a precise description of the Y2O3 sintering process over a wide range of temperatures. In the phase-field method, the microstructure is described by a system of continuous variables that model Y2O3 crystallites, where the microstructure interfaces have a finite width over which the material transfers. The experiments on stepwise sintering process were carried out and the obtained data on the textural and morphological properties of Y2O3 particles were used to calibrate and validate the numerical model. The evolution of the specific surface area and pore volume for the pores ranging from 3 to 70 nm and the rate of growth of Y2O3 crystallites during sintering of Y2O3 grains were effectively predicted. The obtained model indicates that a stepwise increase in the calcination temperature from 600 to 900 and 1200 degrees C decreases the surface area of the materials from 54 to 15 and 5 m(2)/g, respectively. This study can be used to predict the textural properties of yttrium oxide during the sintering of porous ceramics and for the exploitation of catalyst systems.