Stability of Mullite Protective Coatings for Silicon-Based Ceramics

Silicon‐based ceramics are prone to severe oxidation and volatilization problems in the presence of water vapor. To address these issues, mullite has been investigated in recent years as a possible protective coating material. To analyze the stability of such coatings, a multi‐species diffusion mode...

Full description

Saved in:
Bibliographic Details
Published in:Journal of the American Ceramic Society 2005-05, Vol.88 (5), p.1099-1107
Main Authors: Krishnamurthy, Ramanathan, Sheldon, Brian W., Haynes, J. Allen
Format: Article
Language:English
Subjects:
Applied sciences
Building materials. Ceramics. Glasses
Ceramic industries
Ceramics
Chemical industry and chemicals
Cross-disciplinary physics: materials science
rheology
Exact sciences and technology
Materials science
Oxidation
Physics
Protective coatings
Silicon
Structural ceramics
Surface treatments
Technical ceramics
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Silicon‐based ceramics are prone to severe oxidation and volatilization problems in the presence of water vapor. To address these issues, mullite has been investigated in recent years as a possible protective coating material. To analyze the stability of such coatings, a multi‐species diffusion model for ionic species is developed. Onsager reciprocity is assumed for the mobility coefficients and the resulting moving boundary problem is solved numerically. The formulation also accounts for substantial Si volatilization away from the outer surface of the coating. This model is used to analyze an initial transient leading to the formation of an internal silica layer, a second transient period that follows this silica formation, and a steady‐state regime that can only be attained if Si diffusion is sufficiently fast.
ISSN:0002-7820
1551-2916
DOI:10.1111/j.1551-2916.2005.00169.x