W–CeO2 Core–Shell Powders and Macroscopic Migration of the Shell via Viscous Flow during the Initial Sintering Stage

Abstract

To retard the mutual contact of W grains to inhibit their growth, in this study, CeO2·2H2O was first coated on the surface of pure W (undoped) particles by a weight percentage of 4% using a wet chemical method to prepare CeO2·2H2O-doped W-based (doped) powders, with W particles as the core and CeO2·2H2O as the shell (W–CeO2·2H2O core–shell structure), without hydrogen reduction treatment. The undoped and doped powders were subsequently sintered using a spark plasma sintering (SPS) apparatus to fabricate bulk materials. The macroscopic migration of the CeO2 shell in the core–shell W–CeO2 system via viscous flow during the initial sintering stage was studied through simulations and experiments. The results showed that a core–shell structure with W particles as the core and CeO2·2H2O as the shell was successfully prepared. The doped powder contained approximately 3.97% CeO2, consistent with the designed content of 4%. The shell materials migrated among the selected four sintered powders, filling the pores and contributing to the improvement in the relative density of the sintered bulk.