Effect of the liquid fragility on flash sintering behavior of oxide nanoparticles

Abstract Transient liquid-film formed at the nanoparticle contacts due to the local Joule heating, assists the ultrafast densification of oxide nanopowders by capillarity during flash sintering. The retention of this liquid-film as a residual intergranular amorphous layer or its crystallization depends on the fragility of the liquid-film, hence on its composition. Impurities concentrated at the particle surfaces and grain boundaries modify the flash temperature by affecting the electrical conductivity and viscosity of this liquid-film. These aspects were discussed for flash sintering of pure and doped aluminas as examples from the literature, where doping changed the flash onset temperatures and densification behavior.