Microstructural development of Si{sub 3}N{sub 4} ceramics derived from polymer precursors

Conference · Fri Sep 01 04:00:00 EDT 1995

OSTI ID:99135

Iwamoto, Y; Matsubara, H ^[1]; Brook, R J ^[2]

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1. Japan Fine Ceramics Center, Nagoya (Japan)
2. Univ. of Oxford (United Kingdom)

Silicon nitride (Si{sub 3}N{sub 4}) is a particularly attractive material for high temperature application because of its high-strength, low thermal expansion and thermal shock resistance. Recently, increasing attention has been directed to the use of organometallic polymer precursors such as polysilazane, perhaydropolysilazane and polycarbosilazane. Key reasons for the interest in the preparation of ceramics from these precursors include the easy formation of complex shape, the unique fine microstructure of materials or composites and compositional homogeneity in the final ceramics. The perhydropolysilazane (PHPS) has some advantages in purity and high ceramic yield for the fabrication Of Si{sub 3}N{sub 4} based ceramics. The main aim of this study is the development of a polymer precursor method for the pseudo binary ceramics of Si{sub 3}N{sub 4}-Y{sub 2}O{sub 3} which has excellent high temperature strength. The crystallization, densification and microstructure development were investigated for the ceramics from the PHPS-derived Si-Y-O-N powder, Y{sub 2}O{sub 3}-doped amorphous Si{sub 3}N{sub 4} powder and conventionally processed Y{sub 2}O{sub 3}-doped {alpha}-Si{sub 3}N{sub 4} powder.

• OSTI ID: 99135
• Report Number(s): CONF-940911--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERAMICS
CRYSTALLIZATION
GRAIN REFINEMENT
GRAIN SIZE
MICROSTRUCTURE
POLYMERS
PROCESSING
SILICON NITRIDES
SINTERED MATERIALS
X-RAY DIFFRACTION
YTTRIUM OXIDES