ISSN:
1551-2916
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Three Si3N4 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% H2O–50% O2 gas mixture flowing at 4.4 cm/s, all three types exhibited paralinear kinetics. The material was oxidized by water vapor to form solid SiO2. The protective SiO2 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 SiO2 scale could result in accelerated consumption of Si3N4. Recession rates under conditions more representative of actual combustors were compared with the furnace data.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1151-2916.2003.tb03461.x
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