"This dissertation is comprised of five sections. The first section includes a review of the literature on the development of glass and glass-ceramic sealants for solid oxide fuel cells (SOFC), including the critical issues for sealant design. Section two describes a quantitative approach to characterize the isothermal crystallization of glass using differential thermal analysis (DTA), with Li2O-2SiO2 as the model system. Section three applies this approach using a SOFC sealing glass (glass#27). The finer powder crystallizes much faster than larger particles and the addition of a second phase filler also increases the crystallization rate of the base glass. Surface crystallization dominates in this glass system. Section four includes the quantitative study of reactions between sealing glass and Cr2O3 to understand the formation of deleterious chromate phases. The formation of detrimental phases such as SrCrO4 at the interface between glass-ceramic sealants and stainless steel interconnects depends on the heat treatment temperature, time and atmosphere. It was also found that the formation of SrCrO4 is affected by the addition of ZnO to the sealing glass due to the competing formation of ZnCr2O4. Section five describes the volatility of B2O3 from sealing glasses under SOFC operational conditions. Based on thermodynamic analyses, B2O3 is the most volatile of all oxide components in sealing glasses. The volatility of B2O3 from the glass depends on the atmosphere, time, temperature and B2O3 activity. An increase in mass loss with increasing time at higher temperature in air was observed. The relationship between glass composition and properties are summarized in the appendix. The addition of B2O3 and ZnO decreases glass transition temperature of glasses and thus improves the glass forming tendency. The addition of B2O3 also decreases the softening temperature of glasses. The coefficient of thermal expansion of glasses depends on the average field strength of alkaline earth oxides"--Abstract, page iv.
Brow, Richard K.
Miller, F. Scott, 1956-
Carroll, Douglas R.
Materials Science and Engineering
Ph. D. in Ceramic Engineering
United States. Department of Energy
Missouri University of Science and Technology
Journal article titles appearing in thesis/dissertation
- Determining kinetic parameters for isothermal crystallization of glasses: theory and experimental verification
- Isothermal crystallization of a solid oxide fuel cell sealing glass by differential thermal analysis
- Reaction between Cr₂O₃ and SOFC sealing glasses
- Borate volatility from SOFC sealing glasses
xii, 183 pages
© 2008 Teng Zhang, All rights reserved.
Dissertation - Restricted Access
Solid oxide fuel cells
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Electronic access to the full-text of this document is restricted to Missouri S&T users. Otherwise, request this publication directly from Missouri S&T Library or contact your local library.http://merlin.lib.umsystem.edu/record=b6631876~S5
Zhang, Teng, "Glass-ceramics for solid oxide fuel cell seals" (2008). Doctoral Dissertations. 1766.
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