Characterization of FFF printed parts made of 3Y-TZP and Al2O3 filaments

Abstract

This study focuses on determining the optimal thermal treatment conditions for YSZ and Al₂O₃ samples manufactured using 3D printing technology through Fused Filament Fabrication (FFF), with the aim of achieving superior mechanical and microstructural properties while addressing known issues such as Low Temperature Degradation (LTD) in the case of YSZ. Thermogravimetric analysis (TGA) guided the design of the thermal profiles to ensure controlled removal of organic binders without compromising the structural integrity of the samples. Mass loss and volumetric shrinkage were characterized, confirming that the debinding process removes most of the organic components, while sintering promotes densification. Densification and porosity results were in good agreement with the specifications provided by the supplier (Zetamix) for YSZ, especially after one hour of sintering at 1500 °C, whereas alumina samples showed partially divergent trends, likely due to limited processing conditions. Flexural strength tests revealed that alumina samples closely matched the mechanical performance predicted by Zetamix, while YSZ samples showed lower values due to the presence of microcracks, as confirmed by SEM analysis. Rheological characterization showed a desirable shear-thinning behavior and appropriate yield stress values for both ceramic filaments, confirming their suitability for extrusion-based additive manufacturing. Microstructural studies using FE-SEM and EDS detected alumina inclusions in the YSZ samples, possibly related to mechanical defects, while alumina samples showed homogeneous microstructures with larger grain sizes correlating to higher strength. Overall, this study highlights the critical role of thermal process control in balancing densification, microstructure, and mechanical properties. The results support the potential of these ceramic materials for demanding functional applications, with special emphasis on biomedical implants such as hip prostheses. Further research is recommended involving advanced microstructural analysis, broader mechanical testing, and optimization of 3D printing parameters to mitigate defects and improve final part performance