3D structuring of dense alumina ceramics using fiber-based stereolithography with interparticle photo-cross-linkable slurry

In this paper, we demonstrated optical fiber-based stereolithography of alumina ceramics using concentrated slurry with low monomer content for enabling rapid firing of the printed green objects. Photo cross-linkable alumina slurries were designed using a partial complex of polyethyleneimine and oleic acid (PEI-OA) as reactive polymer dispersants and multifunctional acrylates (MA) as monomers. The effects of the processing parameters, such as oleic acid contents, MA contents, particle contents, and particle sizes, on photocuring properties were systematically investigated. We found that the reactive amine sites of PEI-OA attached to particles and MA volume concentrations in the liquid phase were the most dominant factors to improve the photocuring properties. Therefore, a slurry composed of larger alumina particles with higher solid contents and PEI-OA with lower OA contents was more favorable for achieving photocuring under reduced MA content. The designed photocurable slurry was then applied to ceramic stereolithography using optical fiber. 3D alumina green parts were drawn by passing blue laser beam through an optical fiber in a droplet of photocuring slurry and dense sintered alumina were successfully fabricated by rapid drying (<10 min) and debinding (<1 h) without any structural collapse. (c) 2021 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

Automated summary

In this study, optical fiber-based stereolithography of alumina ceramics was demonstrated using concentrated slurry with low monomer content for rapid firing of printed green objects. The effects of processing parameters on photocuring properties were systematically investigated, and it was found that reactive amine sites in PEI-OA and MA volume concentrations were the most dominant factors for improving photocuring properties. Thus, a slurry composed of larger alumina particles and lower OA content in PEI-OA was more favorable for achieving photocuring under reduced MA content.