Role of microstructure reactivity and surface diffusion in explaining flash (ultra-rapid) sintering kinetics

The competition between sintering and coarsening is cited by numerous authors as one of the potential factors for explaining ultra-rapid kinetics flash sintering. In particular, surface diffusion a mechanism decreasing driving force changing initial highly reactive microstructures (particle contact) into poorly porous skeleton structures (spherical porosity). We show finite element simulations that SPS experiments high specimen temperatures close to 2000 °C. These are not sufficient explain if typical spherical pore theoretical moduli employed. On contrary, experimentally determined succeed in kinetics. Mesoscale evidenced origin such experimental geometry with significant delay particle rearrangement. This highlights important role negation (favoring higher stress intensification factor)