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Paralinear Oxidation of Silicon Nitride in a Water‐Vapor/Oxygen Environment
Author(s) -
Fox Dennis S.,
Opila Elizabeth J.,
Nguyen QuynhGiao N.,
Humphrey Donald L.,
Lewton Susan M.
Publication year - 2003
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.1151-2916.2003.tb03461.x
Subject(s) - water vapor , silicon nitride , volatilisation , kinetics , oxygen , analytical chemistry (journal) , silicon , kinetic energy , chemistry , nitride , chemical vapor deposition , materials science , nanotechnology , environmental chemistry , metallurgy , layer (electronics) , physics , organic chemistry , quantum mechanics
Three Si 3 N 4 materials were exposed to dry oxygen flowing at 0.44 cm/s at temperatures between 1200° and 1400°C. Weight change was measured using a continuously recording microbalance. Parabolic kinetics were observed. When the same materials were exposed to a 50% H 2 O–50% O 2 gas mixture flowing at 4.4 cm/s, all three types exhibited paralinear kinetics. The material was oxidized by water vapor to form solid SiO 2 . The protective SiO 2 was in turn volatilized by water vapor to form primarily gaseous Si(OH) 4 . Nonlinear least‐squares analysis and a paralinear kinetic model were used to determine parabolic and linear rate constants from the kinetic data. Volatilization of the protective SiO 2 scale could result in accelerated consumption of Si 3 N 4 . Recession rates under conditions more representative of actual combustors were compared with the furnace data.