Apparent activation energy for the densification of a commercially available granulated zirconia powder

Sintering in air of a commercially available granulated zirconia powder has been investigated using vertical dilatometer tests. Using several heating rates and the formalism of the constant rate of heating method, it has been possible to determine the apparent activation energy for the mechanism controlling densification, for different values of the relative density. It is shown that the apparent activation energy does not have a single value but depends directly on the relative density.