Vormgeving van dens koper en silicium carbide door 3D-micro-extrusie

This doctoral research investigates the potential of 3D micro-extrusion additive manufacturing as a versatile route for fabricating dense, high-performance copper (Cu) and silicon carbide (SiC) components, extending its application beyond the macro-porous lattice structures typically reported in literature. The work addresses critical limitations of established metal and ceramic additive manufacturing techniques, particularly laser powder bed fusion and stereolithography, which face fundamental challenges in processing Cu and SiC due to their optical and thermal properties. Comprehensive processing routes were developed, encompassing feedstock formulation, extrusion-based shaping, and post-processing steps including drying, thermal debinding, and sintering. For copper, a propanol-based viscous paste containing 95 wt% powder was optimized, with degassing identified as a key factor in eliminating entrapped air and achieving high density. Using optimized printing and sintering conditions, Cu components with densities of 96-99% were produced, exhibiting electrical conductivity near 100% IACS and mechanical properties comparable to conventionally manufactured and state-of-the-art AM Cu. The design freedom of 3D micro-extrusion was demonstrated through the fabrication of complex geometries, and key manufacturing constraints were systematically established, including minimum wall thicknesses, channel sizes, and feasible inclination angles. Lower-temperature sintering was shown to be beneficial in preserving fine features. A Cu gyroid lattice fabricated by this method demonstrated thermal performance comparable to LPBF Cu heat sinks, highlighting the competitiveness of the process. For silicon carbide, a complete processing route employing liquid-phase sintering with Al₂O₃ and Y₂O₃ additives was developed. Dense SiC components (97-98%) were successfully fabricated, exhibiting excellent mechanical and thermal properties that are competitive with high-end conventionally processed SiC and superior to those reported for additively manufactured SiC. Overall, the thesis establishes 3D micro-extrusion as a promising and flexible additive manufacturing technology capable of producing dense bulk metallic and ceramic components with complex geometries and competitive performance, significantly broadening its applicability for advanced functional and structural applications.