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 Usually, ceramics are fabricated and consolidated by sintering powder compacts, but structures with complex geometries are difficult to produce because of limitations in the mould design. Additive manufacturing (AM) allows complex geometries to be made with fewer constraints compared to conventional fabrication techniques. On the other hand, it is becoming more evident that the bottleneck of these technologies is generally not represented by the printing process itself but by the slow thermal debinding and sintering, typically requiring several hours or days.

In this aspect, my research work has been devoted in developing strategies to achieve rapid debinding and sintering of complex structures in a single step lasting from few seconds to minutes. Together with our collaborators at University of Trento, we were able to thermally debind and sinter chemically-debinded (1h in acetone) complex 3YSZ components (produced using filaments from Nanoe) by employing novel ultrafast high-temperature sintering (UHS) in 30–120 s. The sintered components were almost fully dense with no defects even at the microscopic level. For further details, readers can look at our publication: https://doi.org/10.1016/j.jeurceramsoc.2023.08.040, which has been one of the most downloaded research articles in the Journal of the European Ceramic Society(JECS). This promising result further motivated us to extend this novel approach of debinding and sintering to components fabricated with direct ink writing (DIW). With very limited amount of organics in the ink composition, it was possible to achieve rapid debinding and sintering of the BaTiO3 scaffolds using different rapid sintering approaches such as UHS, pressureless-spark plasma sintering (P-SPS) and fast firing (FF). However, because of the associated phase transformation (from tetragonal to hexagonal) when sintered in inert atmospheres, especially for UHS and P-SPS, the densification was limited. Such results prove that while rapid debinding of optimised DIW BaTiO3 is possible both in an inert and air atmosphere, rapid sintering can be effectively accomplished only in the air. Further information related to this can be found in our published article: https://doi.org/10.1111/jace.19950. The application of such novel sintering techniques to additively manufactured components is still in the initial stage, and further validation and exploration is required to better understand the process.

In addition, I have also focused on optimising feedstock for the production of BaTiO3 filaments using a biodegradable thermoplastic blend for the fused filament fabrication process. Filaments with ceramic loading up to 78 wt.% were fabricated and a maximum relative density of 92% after sintering was achieved with a suitable piezoelectric and ferroelectric response. This work was awarded the Best Poster award at yCAM 2024 in Tampere, Finland. More details can be found here : https://doi.org/10.1016/j.addma.2024.104238.

I also take this opportunity to share some of the micrographs that were recognised in the YCN photo contest.

For collaborations or discussion, don’t hesitate to contact me at:

Subhadip Bhandari, PhD student

CERAMGLASS research group, Università degli Studi di Padova, Italy

Group website: https://research.dii.unipd.it/ceramglass/

Email: subhadipbhandari@gmail.com, subhadip.bhandari@phd.unipd.it

LinkedIn : https://it.linkedin.com/in/subhadip-bhandari-188547133

YCN Photo contest 2022       YCN Photo contest 2023             YCN Photo contest 2024