Densification of Reaction Bonded Silicon Nitride with the Addition of Fine Si Powder Effects on the Sinterability and Mechanical Properties

Journal Article · Tue Jan 01 00:00:00 EST 2013 · Journal of the Korean Ceramic Society

DOI:https://doi.org/10.4191/kcers.2013.50.3.218· OSTI ID:1095739

Lee, Sea-Hoon ^[1]; Cho, Chun-Rae ^[1]; Park, Young-Jo ^[1]; Ko, Jae-Woong ^[1]; Kim, Hai-Doo ^[1]; Lin, Hua-Tay ^[2]; Becher, Paul F ^[2]

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1. Korea Institute of Materials Science
2. ORNL

The densification behavior and strength of sintered reaction bonded silicon nitrides (SRBSN) that contain Lu2O3-SiO2 additives were improved by the addition of fine Si powder. Dense specimens (relative density: 99.5%) were obtained by gas-pressure sintering (GPS) at 1850oC through the addition of fine Si. In contrast, the densification of conventional specimens did not complete at 1950oC. The fine Si decreased the onset temperature of shrinkage and increased the shrinkage rate because the additive helped the compaction of green bodies and induced the formation of fine Si3N4 particles after nitridation and sintering at and above 1600oC. The amount of residual SiO2 within the specimens was not strongly affected by adding fine Si powder because most of the SiO2 layer that had formed on the fine Si particles decomposed during nitridation. The maximum strength and fracture toughness of the specimens were 991 MPa and 8.0 MPa m1/2, respectively.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: Work for Others (WFO)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1095739
• Journal Information: Journal of the Korean Ceramic Society, Vol. 50, Issue 3; ISSN 1229--7801
• Country of Publication: United States
• Language: English