In the recent years, ultrafast sintering techniques have gained popularity as a way to reduce the processing time and energy consumption of the ceramic industry. However, most of the research study has focused on the field-assisted sintering of uniaxially or isostatically pressed powder compacts with simple shapes. Additive manufacturing (AM) allows fabricating complex geometries with fewer constraints compared to the conventional fabrication techniques. On the other hand, it is becoming more evident that the bottleneck of these technologies is not represented by the printing process itself, but by the slow thermal debinding and sintering, typically requiring several hours or days.
 

In this work, 3D printed cylindrical structures of 3 mol% yttria-stabilized zirconia with gyroidal infill pattern were fabricated using the fused filament fabrication process (FFF). This research study examines the use of ultra-fast high-temperature sintering (UHS) to densify the complex 3D structure. A systematic study was done on the sintering behaviour of the as-printed, chemically debinded and pre-sintered samples. Furthermore, current-controlled experiments with the help of FEM simulation were performed to study the densification behaviour. With optimized parameters, the 3D printed, chemically debinded samples were thermally debinded and sintered (up to almost full density) in a single-step process that takes 30 to 120 s depending on the UHS conditions. This work provides a first proof of concept on employing ultrafast heating rates to sinter such complex geometries without going through a separate thermal debinding process, reducing the overall processing time by 99%.