Polyethylene–SiC Composite Filaments: Processing, Printability, and Formation of Porous SiC Preform via Additive Manufacturing

Polyethylene/silicon carbide (PE/SiC) composite filaments containing Al 2 O 3 and Y 2 O 3 as sintering aids were developed for fused filament fabrication (FFF). Feedstocks with 50–65 wt% SiC were prepared by melt compounding and filament extrusion. The formulation with 60 wt% SiC exhibited the most stable extrusion behavior, uniform filament diameter (1.75 ± 0.05 mm), and reliable printability. As-printed green specimens showed sufficient mechanical integrity, with an ultimate tensile strength of 0.94 ± 0.06 MPa and a Young’s modulus of 48 ± 3 MPa. Thermal analysis confirmed complete binder removal above 500 °C without ceramic degradation. After debinding and pre-sintering at 1200 °C under argon, porous SiC preforms with an interconnected ceramic framework were obtained, exhibiting a bulk density of 1.73 ± 0.03 g·cm -3 , 35 ± 1% open porosity, and a Vickers hardness of 1350 ± 12 HV. These results demonstrate that the developed PE/SiC feedstock enables the fabrication of mechanically stable porous SiC preforms suitable for subsequent high-temperature densification or functional porous ceramic applications.