Rapid sintering of 3 mol % Y₂O₃-doped ZrO₂ by a combined rapid furnace heating and shrinkage-controlled flash sintering protocol

Abstract

Flash sintering has attracted much attention as a useful sintering technique that is able to lower the sintering furnace temperature and shorten the sintering time. To further improve this original flash sintering technique, we have developed a technique to facilitate shrinkage at a constant shrinkage rate by controlling the power dissipation during a flash state, which is termed as shrinkage-controlled flash (SCF) sintering. Here, we combine this SCF sintering method with a rapid furnace heating process to shorten the entire sintering process time. Accordingly, we succeed in sintering 3 mol % Y₂O₃-doped ZrO₂ (3YSZ) polycrystals with a high density of 6.05 g/cm³ and a uniform grain size of approximately 0.47 µm with a short sintering time of approximately 40 min. The obtained 3YSZ polycrystals are confirmed to exhibit a Vickers hardness and fracture toughness [by an indentation fracture method] of approximately 1295 HV and 5.3 MPa m^1/2, respectively.