Hostname: page-component-cd9895bd7-dk4vv Total loading time: 0 Render date: 2024-12-26T02:49:12.056Z Has data issue: false hasContentIssue false
  • English
  • Français

Phase Transformations in Multilayered CVD Mullite Coatings

Published online by Cambridge University Press:  15 February 2011

D. Doppalapudi ,
R. Muipuri ,
S. N. Basu  and
V. K. Sarin
D. Doppalapudi
Affiliation:
Department of Manufacturing Engineering, Boston University, Boston, MA 02215
R. Muipuri
Affiliation:
Department of Manufacturing Engineering, Boston University, Boston, MA 02215
S. N. Basu
Affiliation:
Department of Manufacturing Engineering, Boston University, Boston, MA 02215
V. K. Sarin
Affiliation:
Department of Manufacturing Engineering, Boston University, Boston, MA 02215
Get access

Abstract

Mullite (3Al2O3.2SiO2) is an ideal candidate for coatings on SiC due to its toughness, corrosion resistance and coefficient of thermal expansion (CTE) match. We have deposited alternating layers of Al2O3 and SiO2 followed by post deposition heat treatment to induce mullite formation at the interface. We found that the devitrification of silica to cristobalite led to spallation of the multilayered coatings due to the fracture within the crystalline silica layers. To understand this transformation better, we studied the effect of pressure and temperature on devitrification of silica in both bulk and in coating form. We have demonstrated that the difference in specific volumes of the two phases plays a key role in the vitreous to crystalline transformation in silica.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 363 , 1994 , 95
Copyright
Copyright © Materials Research Society 1995

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Federer, J.I., Adv. Ceram. Mater., 3 [1] 56 (1988).Google Scholar
2. Aksay, I.A., and Pask, J.A., J. Am. Ceram. Soc., 58 [11–12] 507 (1975).Google Scholar
3. Oertel, G., and Flietner, H., “Isolationsschichten Auf Germanium Und Deren Elektrische Eigenschaften,” Proceedings of the Second Colloquium on thin Films, 626–635 (1967).Google Scholar
4. Wagstaff, F.E., J. Am. Ceram. Soc., 52 [12] 650 (1969).Google Scholar
5. MCIC Report, Engineering Property Data on Selected Ceramics Volume III. Single Oxides, MCIC-HB-07, Metals and Ceramics Information Center, Columbus, Ohio (1981).Google Scholar