Activation Energy of Densification of Alumina: Comparison of Different Formulations

ABSTRACT

The activation energy of densification is an important parameter that not only controls the kinetics of densification and microstructure evolution but also provides information on the dominant transport mechanisms. In the literature, various approaches have been used to calculate the activation energy of sintering from experimental results on densification kinetics. In this study, using the same experimental data set on high‐purity alumina, the activation energy of densification has been calculated using three different, well established formulations, specifically: The master sintering curve, the Wang and Raj kinetic formulation, and the continuum formulation. The results show that the activation energy calculated from the three formulations are comparable. This implies that the assumptions used in the three formulations are validated. Further, for well controlled uniform green compacts, any of the three approaches are suitable to calculate the activation energy for densification. Conversely, if the calculated activation energy is the same for the different approaches, it shows that the common assumption in the three approaches, namely, one dominant kinetic mechanism for densification, is valid.