Development of Optimized Alumina Suspensions for Additive Manufacturing of Ceramic Parts via Direct Ink Writing (DIW)

• Grant number: 24/19331-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2025
• End date: December 31, 2025
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Ana Paula da Luz
• Grantee: Gabriel Hercules Navarro
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Alumina ceramics (Al2O3) are among the most extensively used advanced ceramics across various industries. However, traditional forming methods have struggled to meet the increasing demands for intricate geometries and high-precision manufacturing required for advanced functional applications. Additive manufacturing technologies are gaining significant attention due to their ability to produce complex, customized shapes. Among these, the extrusion-based process known as direct ink writing (DIW) stands out for its adaptability, simplicity, and environmental friendliness, making it a popular method for fabricating ceramic components. The design of the ceramic suspension (paste) is a critical factor in the DIW process. A suitable suspension must exhibit excellent homogeneity, a sufficiently high ceramic loading to minimize shrinkage, and the appropriate rheological properties to allow for smooth extrusion while maintaining shape stability after deposition. This project focuses on the development and characterization of alumina suspensions tailored for DIW-based ceramic part production. Several key parameters will be assessed, including solids content (45 to 50 vol%), the type and concentration of dispersant, and the type and concentration of binder/coagulant (e.g., methylcellulose or polyethyleneimine, PEI). Rheological testing of the pastes, analysis of filament collapse, and characterization of the printed parts-including mechanical strength, shrinkage, porosity, and microstructural properties before and after firing-will be conducted. The primary objective is to develop stable suspensions with optimal rheological properties, enabling the fabrication of high-quality ceramic parts that, after sintering, demonstrate optimized microstructures with minimal defects. Additionally, the effects of various additives on suspension viscosity and the final characteristics of the printed parts will be investigated.