Morphological Evolution and Weak Interface Development within Chemical-Vapor-Deposited Zirconia Coating Deposited on Hi-Nicalon™ Fiber

• Published in: Journal of the American Ceramic Society 2002-06, Vol.85 (6), p.1561-1568
• Main Authors: Li, Hao, Lee, Jinil, Libera, Matthew R., Lee, Woo Y., Kebbede, Anteneh, Lance, Michael J., Wang, Hongyu, Morscher, Gregory N.
• Format: Article
• Language: English
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; ceramic matrix composites; ceramic matrix composites, fiber coating; Chemical industry and chemicals; chemical vapor deposition; Exact sciences and technology; fiber coating; Miscellaneous; morphology; Technical ceramics; zirconia
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1151-2916.2002.tb00312.x

The phase contents and morphology of a ZrO2 fiber coating deposited at 1050°C on Hi‐NicalonTM by chemical vapor deposition (CVD) were examined as a function of deposition time from 5–120 min. The morphological evolution in the ZrO2 coating was correlated to the development of delamination within the ZrO2 coating. The delamination appears to occur as a result of: (i) continuous formation of tetragonal ZrO2 nuclei on the deposition surface; (ii) martensitic transformation of the tetragonal phase to a monoclinic phase on reaching a critical grain size; and (iii) development of significant compressive hoop stresses because of the volume dilation associated with the transformation. Our observations suggest that it will be of critical importance to further understand and eventually control the nucleation and grain growth behavior of CVD ZrO2 and its phase transformation behavior for its potential applications for composites.