Additive manufacturing of calcium carbonate parts through vat-photopolymerization and sintering in carbon dioxide atmosphere

Although calcium carbonate is more commonly used in powder form, it could have exciting applications in bulk form, such as bone scaffolds, synthetic corals, and artificial rocks. Additive manufacturing (vat-photopolymerization) is a promising strategy for producing parts with complex geometries. However, two main challenges arise: 1) Producing a CaCO3 suspension with high solid loading and low viscosity suitable to ordinary bottom-up 3D printers; 2) Debinding and sintering the CaCO3 parts without causing their thermal decomposition. The first challenge was addressed by following a systematic methodology to select the monomer and dispersant, resulting in a printable 35 vol% CaCO3 suspension with low viscosity (0.28 Pa s at 30s−1). The second challenge was overcome by debinding in air atmosphere to remove all organics, followed by sintering in CO2 above 500 °C to avoid the calcination of CaCO3. The presented results are an important advance for the fabrication of calcium carbonate parts with complex geometries.