Printing uniform, high-strength SiC ceramics at 1100 °C in one step

Published in International Journal of Extreme Manufacturing, a new 3D printing method is developed to create strong, high-quality silicon carbide (SiC) ceramic parts at much lower temperatures than previously possible.

By introducing methyl-phenyl-polysiloxane (PSO) to photo-curable resin system via vat-polymerization, researchers at Shenzhen University successfully printed SiC-based ceramics at just 1100 °C, a temperature far below what's normally required. This approach also allows precise control over the material's anisotropy, a common challenge in 3D-printed ceramics, after sintering.

Traditionally, the manufacture of SiC ceramics has been hampered by the material’s inherent hardness and brittleness, which make shaping difficult. While 3D printing offers a way to produce complex parts, it usually demands very high temperatures and results in uneven mechanical properties—where parts are weaker in certain directions, a problem known as anisotropy.

To solve these issues, the team used vat polymerization, a type of 3D printing where liquid resin is cured layer by layer using light. They also added silica to improve the quality of the printed material and incorporated PSO to make the printed parts much stronger.

As a result, the SiC/SiO₂/PSO ceramic lattices achieved a compressive strength of 89.99 ± 14.76 MPa and a bending strength of 95.49 ± 8.79 MPa—comparable to ceramics sintered at much higher temperatures. These parts also exhibited a high specific strength of 1.03 × 10⁵ N·m·kg⁻¹ and a low density of 1.75 g·cm⁻³, outperforming similar SiC-based lattice structures with comparable porosity.

The team attributes this enhancement to the formation of silicon carbide oxide (SiOC) phase during the process. This phase filled the tiny gaps between printed layers—common in digital light processing (DLP) 3D printing—resulting in better bonding and more uniform strength throughout the part. The strength difference between directions (anisotropy) was greatly reduced: the ratio of transverse to longitudinal strength dropped from 1.87 to 1.08, meaning the parts were almost equally strong in all directions.

The method avoids the need for non-silicon binders and offers a practical, low-temperature route to high-purity, high-strength SiC ceramics. The researchers say this could facilitate more efficient and economical production of structural ceramics for use in extreme environments.

International Journal of Extreme Manufacturing (IJEM, IF: 21.3) is dedicated to publishing the best advanced manufacturing research with extreme dimensions to address both the fundamental scientific challenges and significant engineering needs.

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