Preparation, microstructure and hydrothermal aging behavior of Ce/Y Co-doped tetragonal zirconia-based dental ceramics.

Abstract

Objectives: The present study synthesizes cerium (Ce)/yttrium (Y) co-doped zirconia ceramic powder by the sol-gel method, with the effect of a two-step sintering protocol on the microstructure, phase type, physical and mechanical properties, and resistant hydrothermal aging of zirconia ceramics with different Ce and Y dopant concentrations.

Methods: The ceramic samples were prepared by means of spark plasma sintering (SPS) and post-sintering (P) using Ce/Y co-doped zirconia powder. The surface morphology and element distribution of the samples were characterized by scanning electron microscope (SEM) coupled with energy dispersive spectrometer (EDS); With the help of ImageJ software, the grain size distribution was extracted from SEM images. X-ray diffraction (XRD) analysis was performed to examine the phase composition of the prepared powders and ceramic samples before and after hydrothermal aging. Furthermore, the relative density, Vickers hardness and fracture toughness of the ceramic samples were systematically measured.

Results: The results indicated that the grain size of Ce/Y co-doped zirconia powder diminished with increasing doping concentration, reaching a minimum of 31.07 nm. This trend was mirrored in the ceramic samples fabricated via SPS or SPS-P, with their grain size variation aligning with that of the powder. Notably, the SPS ceramics achieved a relative density of 5.75 g/cm³, a Vickers hardness of 10.29 GPa and a fracture toughness of 6.42 MPa·m^1/2. In contrast, the SPS-P ceramics attained a relative density of 6.22 g/cm³, a Vickers hardness of 10.34 GPa and a fracture toughness of 6.55 MPa·m^1/2. Furthermore, hydrothermal aging treatment results highlighted the ceramics prepared by SPS exhibited superior resistance to hydrothermal aging compared to those prepared by SPS-P.

Significance: In this study, Ce/Y co-doped zirconia powders and ceramics were prepared, and the influence law of doping concentration on their microstructure and macroscopic properties was systematically analyzed, and new ideas were provided to enhance the material properties.