Influence of small amounts of transition metal oxides on spark plasma sintering of nano- Y2O3

This study investigates the effects of small amounts of sintering additives (99.0 %) Y 2 O 3 ceramics with an average grain size of 300 nm were obtained by SPS of pure Y 2 O 3 at 1250°C for 15 min, the addition of dopants resulted in decreased densification and accelerated grain growth, with grain sizes up to 6.5 μm. The correlation between dopant concentration, ionic size, and their effects was inconsistent, particularly for MnO. Thermodynamic analyses and X-ray photoelectron spectroscopy (XPS) indicated that manganese redox transitions at elevated temperatures influence dopant behavior. These results demonstrate that even sub-mol% dopant levels significantly affect sintering pathways, challenging traditional views on low-level doping in refractory ceramics.