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Materials Science in Additive Manufacturing Ceramic vat photopolymerization

A B

C D

Figure 8. Lattice structures after printing and pyrolysis at different temperatures. Left: digital models and sample photos. Right: (A-D)
Microscopic images of the detailed surface features after pyrolysis (diagrams reused under the terms of the Creative Commons CC-BY license)
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During the pyrolysis of polymer-derived ceramics, the decomposition of organic functional groups generates small molecular gases that continuously and
disorderly escape from the structure. This uncontrolled gas release often leads to defects such as cracking, warping, and structural collapse, severely limiting
dimensional accuracy, surface morphology, and achievable component size – a critical challenge in precursor-derived ceramic additive manufacturing.
To address this issue, Chen’s group proposed an innovative approach by introducing low-melting-point additives or specific organic modifiers into the
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photosensitive resin formulation. These additives create physical microchannels during pyrolysis through their own continuous gas emission, providing
organized pathways for the controlled release of macromolecular decomposition gases. This mechanism effectively mitigates internal stress accumulation,
thereby suppressing crack formation, minimizing dimensional distortion, and preventing structural collapse. Consequently, precursor-derived ceramic
components with enhanced precision, improved surface roughness, reduced warpage, and increased critical thickness (cellular skeleton thickness exceeding
2 mm and bulk body thickness surpassing 5 mm) have been successfully fabricated, as demonstrated in Figure 9. Compared with conventional crack-
control techniques such as hot pressing, hot isostatic pressing, and spark plasma sintering, this method offers distinct advantages including simplified
processing (ambient pressure operation), reduced cycle time, and cost-effectiveness.

full ceramization into dense SiOC. Despite a low shrinkage of pre-ceramic polymers during pyrolysis and
ceramic yield rate (13.5 wt.%) and significant shrinkage hence various parameters, such as temperature, heating
(59.91%), the method successfully produces crack-free, rate, and composition, must be controlled. 3D SiCN
geometrically complex ceramics through UV-curable nano/microstructures in a resolution of a few hundreds of
resin design and stress management. Flexible green nanometers were first fabricated by Pham et al. using TPP
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bodies from photopolymerization allow manual folding an inorganic pre-ceramic polymer with a linear shrinkage
into intricate shapes (e.g., spirals, flowers) that retain of ~ 41%. Further, they resolved the issue of shrinkage by
structural integrity after pyrolysis (Figure 10). Material incorporating 10 nm silica particles into the pre-ceramic
characterization confirms chemical bond evolution, polymer and were able to achieve nearly zero shrinkage of
microchannel formation, and defect-free microstructures, the final ceramic component for a solid content of 40 wt.%.
while mechanical testing reveals a compressive strength of The TPP technique has been employed as a template-
21.31 MPa. This strategy bridges additive manufacturing based approach for producing hollow ceramic nanolattices.
and ceramic processing, enabling high-precision, defect- This technique involves three key steps: (i) TPP fabrication
resistant PDCs for aerospace and biomedical applications. of nanoscale polymer molds, (ii) conformal deposition of

TPP has also been explored at a large scale for ceramic materials (TiN, Al O ) via vapor-phase techniques,
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the fabrication of polymeric materials for optical and (iii) precision opening of the structure using ion-beam
applications; however, the requirement of complex micro/ milling followed by template removal through chemical
nanostructures for application in harsh environments or plasma etching. Thus, TPP in conjunction with
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has led to the exploration of TPP for the fabrication of appropriate photosensitive pre-ceramic polymers enables
advanced ceramic components. Pre-ceramic polymers fabrication of complex 3D structures of extremely high-
have been proven to be a suitable candidate for fabricating accuracy sub-wavelength features, which are otherwise not
complex structures using TPP and their direct conversion possible with other SL techniques. The challenge associated
to ceramic counterparts via pyrolysis. The limitation is the with this is the difficulty in detaching components from the

Volume 4 Issue 3 (2025) 14 doi: 10.36922/MSAM025200031