Gelcasting of silicon preforms for the production of sintered reaction-bonded silicon nitride

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:172474

Kiggans, Jr, J O; Nunn, S D; Tiegs, T N; Davisson, C C; Coffey, D W ^[1]; Maria, J P ^[2]

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1. Oak Ridge National Lab., TN (United States)
2. Pennsylvania State Univ., University Park, PA (United States)

Gelcasting of silicon metal for the production of sintered reaction-bonded silicon nitride (SRBSN) was investigated in order to identify associated advantages over conventional forming techniques, i.e., die and isostatic pressing. Compacts were formed from identical powder mixtures by both gelcasting and pressing, and were nitrided and sintered to produce SRBSN ceramics using both conventional and microwave heating. Characterization of the samples included measurement of green density, green and nitrided pore structure, weight gain during nitridation, final density, microstructure, toughness, and flexural strength. It was found that a more uniform pore structure existed in the green gelcast samples. It is believed that this pore configuration aided in nitridation, and manifested itself in a more uniform final microstructure. In addition, improved mechanical properties were achieved in the gelcast samples. This improvement can be attributed to green microstructure homogeneity. An additional finding of this study was that microwave hearing combined with gelcast forming resulted in SRBSN materials with improved mechanical properties.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 172474
• Report Number(s): CONF-9505313--1; ON: DE96003764
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CASTING
CASTING MOLDS
CERAMICS
POWDER METALLURGY
SILICON
SILICON NITRIDES
SINTERED MATERIALS
SINTERING