Investigation of the cold sintering densification kinetics and microstructural evolution
Open Access
- Author:
- Bang, Sun Hwi
- Graduate Program:
- Materials Science and Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- September 02, 2022
- Committee Members:
- Michael Lanagan, Outside Unit & Field Member
Allison Beese, Major Field Member
John Mauro, Major Field Member
Clive Randall, Chair & Dissertation Advisor
John Mauro, Program Head/Chair - Keywords:
- Cold sintering process
Zinc oxide
Densification
Sintering kinetics
Grain growth - Abstract:
- Sintering is an important scientific and industrial processing technique to transform powder into a solid, dense, and monolithic piece. However, as ceramic sintering generally requires high temperatures above 1000 °C, decreasing the processing temperature has been a technological and environmental challenge. Among non-conventional sintering methods, the cold sintering process features material densification at significantly reduced processing time and temperatures, typically below 20% of the material melting points, and it has been considered as an emerging method to develop functional composite materials for various electroceramic applications. Despite its scientific and technological importance, the fundamental understanding of the cold sintering kinetics and densification mechanism is still in the very early stages of investigation. The core objectives of understanding sintering kinetics are to predict the densification behavior under different processing conditions and to obtain a uniform microstructure at high density with controlled grain shape and size. The proposed research study takes zinc oxide as a model cold sintering system and identifies the process kinetics and mechanisms. Such an investigation finds the relationship between the process parameters and transient microstructure and chemical evolution. Based on the outcomes, the pilot scale-up and continuous processes have been developed, which demonstrates the possible transition from fundamental research to application development.