REACTION FLASH SINTERING OF MULTIPHASE CERAMICS

摘要

A new phenomenon where the application of modest electric fields can lower the sintering temperature well below 1000 ℃, and the time to just a few seconds, is being called flash sintering. For example yttria stabilized zirconia which normally requires several hours at 1400 ℃ can be sintered in mere seconds at 800 ℃ with fields of about 100 V cm~(-1). The method has been applied to various classes of ceramics drawing from semiconductors, electronic or ionic conductors, and insulators. Flash sintering is further accompanied by intense electroluminescence and a non-linear increase in electrical conductivity. A mechanism that can explain the simultaneous rise in chemical diffusion and a change in the electronic structure remains elusive, though the generation of vacancies, interstitials, electrons and holes via Frenkel pairs appears to apply. Non-linear lattice vibrations also appear to be at play.