Densification mechanisms in spark plasma sintering of nanocrystalline ceramics

摘要: Abstract Effect of the particle size on possible electric discharge during SPS was examined. Nanoparticle compacts enable accumulation high charge, and under conventional voltages used for SPS. The critical is both morphological material dependent. early stages densification nanocrystalline powder compact proceed either by plastic deformation or grain-rotation coalescence sliding, aided softening surfaces. active mechanism depends changes in mechanical electrical properties with temperature. Densification 11 nm nc-MgO particles low yield stress proceeds already at 700 °C. However, 34 nm nc-YAG nano-grain rotation surface softening. final associated diffusional processes, where curvature driven grain growth predominates.