Study of the densification and grain growth mechanisms occurring during spark plasma sintering of different submicronic yttria-stabilized zirconia powders

Densification and grain growth mechanisms of Yttria-Stabilized Zirconia sintered by Spark Plasma Sintering are investigated. Sintering trajectories of four commercial submicronic powders with different average particle sizes and yttria amounts have been established and sintering regimes determined. Densification mechanisms are determined in the regime where densification is occurring without grain growth using a model derived from hotpressing. Grain growth mechanisms are determined using the conventional power law in the regime where ceramics are fully densified. Densification occurs by grain boundary sliding accommodated by an in-series interface-reaction/lattice diffusion of cations or by an overlapping of surface diffusion and grain boundary sliding mechanisms for tetragonal stabilized zirconia and by dislocation climbing for fully stabilized zirconia. A normal grain growth occurs for each ceramic, all composed of a single phase, contrary to the two-phased ceramics obtained in literature where grain growth occurs by segregation at grain boundaries.

Automated summary

In this study, densification and grain growth mechanisms of Yttria-Stabilized Zirconia sintered by Spark Plasma Sintering were investigated. The mechanisms were determined based on sintering trajectories of different commercial submicronic powders with varying yttria amounts and particle sizes. Densification was found to occur through grain boundary sliding and other mechanisms, while grain growth followed a power law in fully densified ceramics.