Hot pressing and spark plasma sintering of alumina: Discussion about an analytical modelling used for sintering mechanism determination

The validity of the model for sintering under uniaxial pressure proposed by Bernard-Granger et al. has been investigated by studying the densification kinetics of a submicrometric α-alumina powder using hot pressing and spark plasma sintering devices. The identified key parameters of creep (i.e. stress exponent, apparent activation energy) seem to be unreliable, and do not in the end allow identification of the involved sintering mechanism. Possible biases of the approach are identified and discussed.