| Title |
Comparative Study on the Sintering Behavior and Mechanical Properties of Si3N4 Ceramics with Oxide and Nitrate Additives |
| Authors |
이민호(Min-Ho Lee) ; 손경식(Kyung-Sik Son) ; 이재승(Jae-Seung Lee) ; 김진우(Jin-Woo Kim) ; 안종필(Jong-Pil Ahn) ; 소성민(Sung-Min So) ; 이희수(Hee-soo Lee) |
| DOI |
https://doi.org/10.3365/KJMM.2026.64.6.554 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Silicon nitride; Sintering additive; Nitrate precursor; Microstructure; Sintering behavior; Mechanical |
| Abstract |
In this study, the effects of the chemical form of sintering additives on the sintering behavior and mechanical properties
of Si3N4 ceramics were investigated by comparing an AY composition containing oxide-based sintering additives (Y2O3 and Al2O3)
with an ANYN composition containing nitrate-based precursors (Al(NO3)3·9H2O and Y(NO3)3·6H2O). The nitrate-based
composition was designed based on the assumption that the precursors would be converted into fine oxide phases during heat
treatment, thereby promoting a more homogeneous dispersion of the sintering additives. After fabrication of the sintered specimens,
phase evolution, relative density, flexural strength, Vickers hardness, and fracture toughness were evaluated. In addition, the
microstructure and crack propagation behavior around the indentation impressions were examined to clarify the mechanisms
responsible for the resulting mechanical properties. The results showed that the ANYN composition exhibited higher flexural
strength than the AY composition, and additional flexural tests confirmed a consistent trend of strength improvement. The Vickers
hardness values of the AY and ANYN compositions were comparable, at 18.3 ± 0.8 GPa and 18.8 ± 0.4 GPa, respectively. However,
the fracture toughness slightly increased from 5.48 ± 0.08 MPa·m¹/² for the AY composition to 5.70 ± 0.14 MPa·m¹/² for the ANYN
composition. Microstructural observations revealed that the ANYN composition exhibited a relatively finer and more homogeneous
microstructure, while crack deflection and branching of indentation-induced cracks were more frequently observed. These results
suggest that the use of nitrate-based precursors is beneficial for improving the dispersion uniformity of sintering additives and
controlling the microstructure of Si3N4 ceramics. Consequently, the nitrate-based precursor approach may serve as an effective
strategy for designing sintering additives to enhance the strength and fracture resistance of Si3N4 ceramics. |