Characterization of Si{sub 3}N{sub 4} coated with chemically-vapor-deposited mullite after Na{sub 2}SO{sub 4}-induced corrosion

Journal Article · Sun Sep 01 00:00:00 EDT 1996 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1996.tb09003.x· OSTI ID:417758

Lee, W Y; More, K L; Stinton, D P; Bae, Y W ^[1]

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1. Oak Ridge National Lab., TN (United States)

Si{sub 3}N{sub 4} substrates coated with chemically-vapor-deposited, crystalline mullite (3Al{sub 2}O{sub 3}{center_dot}2SiO{sub 2}) were subjected to a corrosive environment containing Na{sub 2}SO{sub 4} and O{sub 2} at 1,000 C for 100 h. The composition and microstructure of the as-deposited and corroded specimens were examined and compared. The coating appeared to be effective in preserving and therefore protecting the surface microstructure of the underlying Si{sub 3}N{sub 3} substrates. However, a small degree of Na penetration through mullite grain boundaries was observed to a coating depth of {approximately}1 {micro}m.

• Sponsoring Organization: USDOE Assistant Secretary for Energy Efficiency and Renewable Energy, Washington, DC (United States)
• DOE Contract Number: AC05-96OR22464
• OSTI ID: 417758
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 9 Vol. 79; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL COMPOSITION
CHEMICAL VAPOR DEPOSITION
COMPOSITE MATERIALS
CORROSION RESISTANCE
GRAIN BOUNDARIES
HEAT TREATMENTS
MICROSTRUCTURE
MOLTEN SALTS
MULLITE
OXYGEN
SILICON NITRIDES
SODIUM SULFATES