Electric field-assisted sintering (FAST) is gaining interest in recent years due to the accelerated consolidation compared to conventional, pressureless sintering. In particular, flash-sintering, where densification occurs almost immediately (typically <5 seconds) under high DC electric field, has attracted extensive attention as an innovative sintering technique since the first report by Professor Raj’s group in 2010. The flash sintering is also characterized by a nonlinear increase in electric conductivity under a threshold condition of temperature and applied field. The flash sintering has been demonstrated in various ceramics, and nearly full density has been achieved at relatively low furnace temperature for very short time.
We have recently demonstrated that dielectric oxide ceramics such as Y2O3, MgAl2O4 and BaTiO3 can be consolidated at relatively low sintering temperature and short sintering time by flash sintering technique. Microstructural observations and analyses by high-resolution transmission electron microscopy indicated that the electric current flows produced strongly-reducing conditions in the oxide compacts. In the present paper, our results on the flash-sintering behavior of oxide ceramics are briefly summarized, and recent attempts for plastic forming based on the flash event are introduced.