Novel low-shrinkage and soluble heavy calcium carbonate matrix ceramic cores prepared by binder jetting

In the present work, the novel low-shrinkage and soluble heavy calcium carbonate matrix ceramic cores were developed using binder jetting (BJ) technology with SiO₂ as an additive and heavy calcium carbonate (HCC, CaMg(CO₃)₂) as the matrix material. The effect of SiO₂ content on the sintering shrinkage, properties and solubility of the ceramic cores was systematically investigated. It was found that the addition of SiO₂ significantly improved the shrinkage of the ceramic cores. As the amount of SiO₂ increased, the shrinkage in all axes of the ceramic cores decreased, but excessive SiO₂ led to excessive liquid phase sintering, which caused an increase in shrinkage. When the SiO₂ addition was 6 wt%, the shrinkages in the X, Y, and Z axes were 7.09, 7.48, and 9.45 %, respectively, representing a 70 % decrease compared to the cores without SiO₂. Conversely, the bending strength of the ceramic cores initially decreased and then increased with the increase in SiO₂ content. The lowest bending strength of 4.93 MPa was observed at 6 wt% SiO₂ content. Although the strength of the ceramic cores is lower under this condition, it still meets the requirements for practical production. The soluble ceramic cores begin to disintegrate after being immersed in hot water for 10 min, with significant disintegration observed after 60 min, indicating that the ceramic cores fabricated in this study possess good solubility.