Silicon nitride joining

Journal Article · Sun Sep 01 04:00:00 EDT 1985 · J. Am. Ceram. Soc.; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1985.tb15811.x· OSTI ID:6323593

Mecartney, M L; Loehman, R E; Sinclair, R

Hot-pressed Si/sub 3/N/sub 4/ was joined using an MgO-Al/sub 2/O/sub 3/-SiO/sub 2/ glass composition chosen to approximate the oxide portion of the grain-boundary phase in the ceramic. After it has been heated at 1550/sup 0/ to 1650/sup 0/C, the interface of the joined ceramic is an interlocking mixture of Si/sub 2/N/sub 2/O, ..beta..-Si/sub 3/N/sub 4/, and a residual oxynitride glass. The kinetics of reactions between Si/sub 3/N/sub 4/ and the molten joining composition were studied by X-ray diffraction analysis of the phases present in Si/sub 3/N/sub 4/ powder-glass mixtures quenched after varied heat treatments. Analytical transmission electron microscopy of the composition and microstructure of the reaction zone in joined specimens, together with the X-ray diffraction results, suggests that the driving force for joining is the lowering of the Si/sub 3/N/sub 4/ interfacial energy when it is wet by the molten silicate, augmented by the negative Gibbs energy for the reaction SiO/sub 2/(..integral..) + Si/sub 3/N/sub 4/ = 2Si/sub 2/N/sub 2/O.

• Research Organization: Stanford University, Stanford, California
• OSTI ID: 6323593
• Journal Information: J. Am. Ceram. Soc.; (United States), Journal Name: J. Am. Ceram. Soc.; (United States) Vol. 68:9; ISSN JACTA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360601 -- Other Materials-- Preparation & Manufacture
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CERAMICS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
COHERENT SCATTERING
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
DIFFRACTION
ELECTRON MICROSCOPY
ENERGY
FABRICATION
FREE ENTHALPY
GLASS
GRAIN BOUNDARIES
HOT WORKING
INTERFACES
JOINING
KINETICS
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MATERIALS WORKING
MICROSCOPY
MICROSTRUCTURE
NITRIDES
NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PNICTIDES
POWDERS
PRESSING
REACTION KINETICS
SCATTERING
SILICON COMPOUNDS
SILICON NITRIDES
SILICON OXIDES
THERMODYNAMIC PROPERTIES
TRANSMISSION ELECTRON MICROSCOPY
VERY HIGH TEMPERATURE
X-RAY DIFFRACTION