Near-full compaction within only 30 min of total sintering time by shrinkage-rate-controlled flash sintering in 3 mol % Y₂O₃-doped ZrO₂ polycrystal

Abstract

The development of a high-speed sintering method that can shorten the entire sintering time while guaranteeing the mechanical properties is very attractive as a sintering process for structural ceramic polycrystals. For this purpose, a sintering protocol that combines shrinkage-rate-controlled flash sintering, which controls the shrinkage rate to be constant with the use of an alternative current electric field, and a rapid furnace ramp were applied to 3-mol % Y2O3-doped ZrO2 (3YSZ). As a result, a 3YSZ sintered polycrystal with about the relative density of 99.5 % (6.06 g/cm3) could be successfully fabricated within 30 min as the entire sintering time, which includes the furnace-heating regime. The sintered 3YSZ polycrystal is confirmed to exhibit a Vickers hardness of approximately 1290 HV and a fracture toughness (KIC) of approximately 5.2 MPa m1/2, which are similar values to those obtained from a typical thermally sintered 3YSZ polycrystal.