03/12/2025
By Danielle Fretwell
Candidate Name: Olorunfemi James Esan
Degree: Doctoral
Defense Date: Tuesday, March 25th, 2025
Time: 2:30 - 4:30 p.m.
Location: SAAB ETIC, Room 245
Committee:
Advisor: Amy Peterson, Professor, Plastics Engineering, University of Massachusetts Lowell
Committee Members*
1. Jay Park, Associate Professor, Plastics Engineering, University of Massachusetts Lowell
2. Christopher Hansen, Professor, Mechanical Engineering, University of Massachusetts Lowell
3. Alireza Amirkhizi, Associate Professor, Mechanical Engineering, University of Massachusetts Lowell
Brief Abstract:
The use of ceramics in industries including aerospace, electronics, energy, defense, and biotechnology has greatly increased, making it an essential component in many modern technologies. Ceramic structures can be formed (e.g., through injection molding) or additively manufactured AM (e.g., extrusion-based 3D printing). However, the fabrication of large-scale ceramic structures has been hindered by the time-consuming nature of the manufacturing process. In binder-based ceramic manufacturing, the binder is used as a processing aid, which must be removed through a debinding process to obtain the final part. Debinding techniques such as thermal debinding can become long, and energy intensive. In contrast, polymers exhibit excellent toughness, flexibility and ductility. Combining these materials (polymer and ceramic) can enable parts with distinct properties and functionalities. However, the vastly different processing temperatures pose a significant limitation in fabricating these materials simultaneously without degrading the polymer at high temperatures. AM’s design flexibility, which allows for precise material placement within a structure, presents an opportunity to improve the debinding process and manage the thermal state between these dissimilar materials.
This dissertation provides new insights into the processing of large-scale ceramic structures and design approaches for multi-material polymer-ceramic AM, expanding the range of material systems that can be fabricated. The integration of mass transport networks within ceramic structures was investigated to improve gas diffusion during debinding, thereby enabling the fabrication of larger geometries while significantly reducing debinding times. The influence of gradient particle size distributions on capillary-driven binder migration was studied, enabling faster volatilization. Building on these findings, multi-material AM approaches that enable integration of polymers and ceramics during processing were explored. Overall, this work contributes to a deeper understanding of how binder removal times can be shortened while identifying designs and processing methods for achieving desirable property combinations in dissimilar material systems.