Atomic Scale to Micro Scale Understanding of Low Temperature Degradation Mechanism in Zirconia-Based Ceramics

NON-TECHNICAL DESCRIPTION: Zirconia-based ceramics such as yttria-stabilized tetragonal zirconia possess a unique combination of advantageous mechanical, electrical, and chemical properties as well as biocompatibility, which has allowed for a wide variety of applications (orthopedics and dental implants, thermal barrier coatings for turbine engines, oxygen sensors, and solid oxide fuel cell electrolytes). However, a key issue remains in these material systems, namely the occurrence of phase transformation when a stimulus (e.g., low temperature) is applied that degrades the mechanical properties and stability of this material system.

Although zirconia-based ceramics are one of the most studied ceramic systems, there is a lack of understanding in terms of the mechanism causing this low temperature degradation. This project aims to close this gap by using integrated multiscale microscopy techniques and material informatics to establish a quantitative understanding of the phase transformation.

The proposed methodology, acquired learning, and data analysis methods create a pathway for the optimization of materials and their performance. This is critical for many fields such as energy, structural, and biomedical applications . For example, preventing early-onset of low temperature degradation in zirconia-based ceramics widely used in the fabrication of dental crowns and fixed dental prostheses will extend the longevity of ceramic dental implants.

The educational and workforce development activities impact graduate, undergraduate, and K-12 students, and the community to enhance the global competitiveness of the national engineers and scientists. New knowledge is disseminated in an education toolkit designed to explain the principles of atomic scale microscopy. Tutorials at the Materials Research Society and Microscopy and Microanalysis meetings stand to impact students at various levels.

TECHNICAL DETAILS: The research project seeks to gain fundamental understandings of the mechanism of aging-induced low temperature degradation in zirconia-based ceramics. The novel approach of employing advanced microscopy techniques coupled with microstructure informatics provides insights into the local chemistry, grain boundary evolution and oxygen vacancy generation with varying dopant concentration and processing conditions stands to increase the understanding of ceramic systems beyond conventional characterization methods and provide advanced correlation between structural and material performance.

The proposed methodology, acquired learning, and data analysis methods generate a pathway for the optimization of materials and their performance. Graduate and undergraduate students are mentored and trained in this critically important area of ceramic science and technology. Minority K-12 students from South Park High School are inspired and trained through summer research projects.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.