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Silicon Volatility From Alumina and Aluminosilicates Under Solid Oxide Fuel Cell Operating Conditions
Author(s) -
Gentile Paul S.,
Sofie Stephen W.,
Key Camas F.,
Smith Richard J.
Publication year - 2012
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/j.1744-7402.2011.02688.x
Subject(s) - materials science , mullite , oxidizing agent , hydroxide , silane , chemical engineering , oxide , aluminosilicate , volatility (finance) , chemical stability , inorganic chemistry , metallurgy , catalysis , composite material , organic chemistry , chemistry , ceramic , economics , financial economics , engineering
Thermodynamic equilibrium modeling indicates that the introduction of H 2 O in oxidizing environments decreases Si stability due to formation of volatile hydroxide and oxy hydroxides. 3 Al 2 O 3 ·2 SiO 2 mullite bond offers only slight improvement over pure silica as the thermodynamic activity of silica in mullite is near unity. In reducing atmospheres Si stability is improved by the presence of H 2 O and Al 2 O 3 , transitioning from SiO and silane as the dominant volatile species to hydroxides, oxy hydroxides, and SiO with increasing water vapor partial pressure. Empirical studies reveal initial rapid releases of Si from stationary solid oxide fuel cell refractory materials followed by slower solid‐state diffusion limited release.