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

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.