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 % Y 2 O 3 -doped ZrO 2 (3YSZ) polycrystals with a high density of 6.05 g/cm 3 and a uniform grain size of approximately 0.47¯m 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.

On the confluence of ultrafast high‐temperature sintering and flash sintering phenomena

“…The same question can be launched at UHS. Indeed the influence of heating rate on sintering has been of interest for a long time, 14,15 although the experiment with graphite sheet heaters for ultrafast heating represents a new development. 16 Indeed, the first application of flash and UHS into products can be traced back to two inventions at the late nineteenth century.…”

Shell-like structure to limit further densification formed during flash sintering under alternative current electric field for 8 mol %Y₂O₃-doped ZrO₂

“…Among them, SCF-sintering protocol is one of the most useful techniques that no shell-like structure is formed and a green compact is densified uniformly, in which the electric current is controlled without the occurrence of a steep power spike. 14),24), 25) In summary, we investigated the cross-sectional microstructure of 8YSZ compact prepared by conventional flash sintering under AC electric field, which exhibits a phenomenon of restricted densification. It was found that a densified portion with a thickness of about 25 ¯m was formed at the periphery of the porous sintered compact with lower density, which is shell-like structure covering a whole of the sintered compact.…”

ZrO2 Matrix Toughened Ceramic Material‐Strength and Toughness

“…Different sintering methods can significantly affect the fracture toughness and mechanical properties of ZrO 2 ceramics. [70][71][72][73] Therefore, it is crucial to select suitable sintering methods according to different application scenarios. [74][75][76] Figure 5 shows the schematics of several common sintering methods.…”