Preparation of 30 mol.% Y-doped hafnia (Hf0.7Y0.3O2-δ) using a modified solid-state reaction method

A pure and well-crystallized Hf0.7Y0.3O2-δ (YSH) powder was synthesized using a modified solid-state reaction method. Water-based milling and freeze drying process were implemented to facilitate powder synthesis and final densification process. The improved powder performance, in aspects of phase development and sintering behaviour, was investigated by systematic comparison between different powder processing procedures. Dense YSH ceramic material with a relative density of 0.975 was successfully obtained using conventional sintering at 1650 °C for 10 h. XRD, SEM and EDS were employed to characterize the synthesized powder and dense YSH ceramics. Dense YSH ceramic possesses a fluorite cubic structure with an a value of 5.1406 Å, and the ionic radius of Y3+ in YSH was determined to be 0.1006 nm.