Self Repairable Seals by Crack Healing of Glass and Glass-Ceramic Composites for Solid Oxide Fuel Cells

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The primary objective of this grant is to establish a fundamental understanding of the crack-healing mechanism in promising glasses and glass-ceramic composites useful for advancing a transformative concept of self-repairable seals for fuel cells. Glasses are used as seals in solid oxide fuel cells (SOFCs) for generating electricity directly. It requires hermetic metal-ceramic seals functioning at 800°C, which is challenging and susceptible to glass seal cracking during operation. To address this challenge, a novel concept of active self-repairable seals driven by surface energy will be pursued. The rationale behind this novel concept is that at the SOFC operating temperature of 800°C a sealing glass with appropriate surface and thermophysical properties can heal or repair cracks created during thermal transients. However, a fundamental understanding of the kinetics and mechanism of crack healing in glasses and glass-ceramic composites is currently lacking. With such an understanding, one can identify the crack-healing/self-repair mechanism and be able to predict the healing time required for achieving self-repair in a functioning SOFC. In addition, the role of the crystalline ceramic phase created either by crystallization of the glass or added intentionally for influencing crack healing behavior will be better understood so that the glass-ceramic composites with optimum load-bearing capability and self-repairability can be designed for use as seals in a SOFC. Through this grant, the PI also will develop analytical models to describe and predict crack-healing and self-repair behaviors observed experimentally.Seals play a critical role in several high-technology areas including SOFCs, vacuum technology, microelectronics, power electronics, and microelectromechanical systems. The proposed research will train graduate and undergraduate students and postdoctoral associates in invaluable technical and research skills applicable to both academia and industry and advance the resources of our institution by new facilities for the synthesis of glasses and glass-composites for high-technology applications. In addition, with the current emphasis on conserving our limited natural resources for energy production, efficient SOFCs will result in direct savings by lower fuel consumption for power generation and environmental impact. The minority/women undergraduate and high school students will be mentored and exposed to this research through Multicultural Engineering Program (MEP), and WEAT (Women In Engineering, Architecture & Technology) programs. A significant outreach to high schools is proposed through ASM materials workshops and camps for teachers and students.