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Optimization of Chemical Vapor Deposition Parameters for Fabrication of Oxidation‐Resistant Mullite Coatings on Silicon Nitride
Author(s) -
Zemskova Svetlana M.,
Jones Camille Y.,
Cooley Kevin M.,
Haynes J. Allen
Publication year - 2004
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2004.tb07491.x
Subject(s) - mullite , chemical vapor deposition , materials science , coating , fabrication , microstructure , chemical engineering , silicon nitride , deposition (geology) , silicon , phase (matter) , mineralogy , composite material , metallurgy , nanotechnology , chemistry , organic chemistry , ceramic , medicine , paleontology , alternative medicine , pathology , sediment , engineering , biology
Fabrication of mullite (3Al 2 O 3 ·2SiO 2 ) coatings by chemical vapor deposition (CVD) using AlCl 3 –SiCl 4 –H 2 –CO 2 gas mixtures was studied. The resultant CVD mullite coating microstructures were sensitive to gas‐phase composition and deposition temperature. Chemical thermodynamic calculations performed on the AlCl 3 –SiCl 4 –H 2 –CO 2 system were used to predict an equilibrium CVD phase diagram. Results from the thermodynamic analysis, process optimization, and effects of various process parameters on coating morphology are discussed. Dense, adherent crystalline CVD mullite coatings ∼2 μm thick were successfully grown on Si 3 N 4 substrates at 1000°C and 10.7 kPa total pressure. The resultant coatings were 001 textured and contained well‐faceted grains ∼0.3–0.5 μm in size.