Improved mechanical properties of silica ceramic cores prepared by 3D printing and sintering processes

In this study, silica ceramic cores were fabricated by stereolithography based-3D printing with improved mechanical properties. To this end, the green bodies were first 3D-printed in different directions, and then debinded samples were sintered at different temperatures. The flexural strengths of the ceramics reached a maximum value of 12.1 MPa at a sintering temperature of 1300°C due to the enhanced α-cristobalite content responsible for the flexural strength at room temperature. Meanwhile, the flexural strengths of ceramics printed by mode 1 (printing performed parallel to the height direction) were much greater than those printed by mode 2 (printing performed perpendicular to the height direction). The anisotropy flexural strength was caused by the weak binding force between layers. Sintered ceramics composed of α-cristobalite, β-cristobalite, and quartz. In sum, the control over the 3D printing parameters and adjustment of the sintering process would result in ceramics with isotropic mechanical properties.