Low-temperature sintering and mechanical property evaluation of nanocrystalline 8 mol% yttria fully stabilized zirconia

Abstract

Fully stabilized zirconia containing 8 mol% yttria (8Y-FSZ) in nanocrystalline form has been synthesized by the coprecipitation method. The formation of an easily filterable hydroxide is facilitated by the addition of ammonium sulfate and polyethylene glycol during precipitation. The precipitate is then calcined to produce nanocrystalline powder. Using this powder, it has been possible to obtain a sintering density of more than 95% at a temperature as low as 1150 degrees C by following a conventional sintering schedule. Adoption of a two-stage sintering schedule, in which heat treatment of the powder compact has been carried out initially to a high temperature, followed by a long holding at a lower temperature, resulted in further lowering of the sintering temperature. Hardness and toughness values have been found to be dependent on the microstructure in low-temperature-sintered samples.