Hot-pressing of active magnesia

Densification maps for spark plasma sintering of nanocrystalline MgO ceramics: Particle coarsening and grain growth effects

“…D = 1.0). The appropriate constants and material properties were used from the literature [8,11,[19][20][21], as shown in Table 1.…”

“…This is done simply by calculating the new particle/grain size according to the growth equation, at the beginning of every step of the numerical integration. The coarsening constants were taken from our recent study [20] while the grain growth constants were taken from Pampuch et al [21] data, where nanocrystalline MgO was hot-pressed at the temperatures and pressures of interest. The grain growth in the experimental curves saturated after several minutes.…”

“…Examples of the growth constants acquired from the literature data on nanocrystalline MgO [20,21] are shown in Table 1.…”

“…The assumption that no coarsening takes place in the heating up period should especially be examined for this type of diagram, for which the initial particle size is kept constant. This assumption is more reasonable in SPS than in hot press or HIP, due to the very short heating up periods (a few minutes), though the reported grain growth kinetics [21] suggest that this effect is not negligible. In reality, different SPS temperatures require different heating up durations, hence, different initial particle size may exist at different temperatures when densification starts.…”

“…When both coarsening (at D < 0.9) and grain growth (at D ≥ 0.9) take place using the experimental kinetic data [20,21], Fig. 3.…”