Topotactic growth of Si[sub 2]ON[sub 2] on SiC

Journal Article · Mon Feb 01 04:00:00 EST 1993 · Acta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-7151(93)90068-4· OSTI ID:6050463

Chadwick, M M ^[1]; Petrovic, J J ^[2]; Danforth, S C ^[3]; Mitchell, T E ^[4]

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1. McMaster Univ., Hamilton, Ontario (Canada). Dept. of Materials Science and Engineering
2. Los Alamos National Lab., NM (United States).
3. Rutgers Unic., Piscataway, NJ (United States). Dept. of Ceramic engineering
4. Los Alamos National Lab., NM (United States)

Specimens consisting of a SiC single crystal imbedded in Si[sub 3]N[sub 4] powder have been prepared by hot isostatic pressing at 1,950 C and then examined by transmission electron microscopy. Columnar grains of orthorhombic Si[sub 2]ON[sub 2] are observed in the interface region between the [alpha] SiC crystal and the polycrystalline Si[sub 3]N[sub 4]. The Si[sub 2]ON[sub 2] is thought to form during cooling by crystallization from a Si-O-N-C liquid phase. The liquid phase results from dissolution of the constituent phases by the SiO[sub 2] present on the powder and crystal surfaces. The Si[sub 2]ON[sub 2] is also found to grow topotactically on the SiC with two orientation relationships. In both cases, [100]Si[sub 2]ON[sub 2] is parallel to one of the three < 11[bar 2]0 >SiC directions, while the (0001) surface of SiC can be parallel to either (001) or one of the two (021) planes of Si[sub 2]ON[sub 2], giving a total of nine orientational variants. Possible atomic models of the interface have been constructed and analyzed. It is found that the observed orientation relationships are such as to optimize the matching of the [SiC[sub 4]] and [SiON[sub 3]] tetrahedra across the interface. In fact, the (001) and (021) planes have the highest planar densities of such tetrahedra in the Si[sub 2]ON[sub 2] structure, as does the (0001) plane in SiC.

• OSTI ID: 6050463
• Journal Information: Acta Metallurgica et Materialia; (United States), Journal Name: Acta Metallurgica et Materialia; (United States) Vol. 41:2; ISSN 0956-7151; ISSN AMATEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
&amp; Refractories-- Structure &amp; Phase Studies
ATOMIC MODELS
CARBIDES
CARBON COMPOUNDS
CHALCOGENIDES
CRYSTAL GROWTH
CRYSTAL-PHASE TRANSFORMATIONS
CRYSTALLIZATION
DISSOLUTION
ELECTRON MICROSCOPY
MATHEMATICAL MODELS
MICROSCOPY
MICROSTRUCTURE
NITRIDES
NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PNICTIDES
SILICON CARBIDES
SILICON COMPOUNDS
SILICON NITRIDES
SILICON OXIDES
TRANSMISSION ELECTRON MICROSCOPY