Improved mechanical properties of SiB6 reinforced silica-based ceramic cores fabricated by 3D stereolithography printing

Abstract

Silica-based ceramic core is an extremely critical component in the manufacture of hollow blades during investment casting. However, the traditional preparation methods rely more on the molds, and the manufacturing costs are relatively high. In this study, silica-based ceramics with silicon hexaboride (SiB6) addition were prepared via 3D stereolithography printing. And the effects of the SiB6 content on mechanical properties of the obtained ceramic samples were explored. As the SiB6 content increased to 2.0 wt%, the linear shrinkage gradually decreased, while the room temperature and high temperature flexural strength were enhanced at the SiB6 content from 0 to 1.0 wt% and reduced as the SiB6 content further rose. As the SiB6 content increased to 1.0 wt%, the linear shrinkage was reduced to 1.86% resulting from the oxidation reaction of SiB6. Furthermore, with 1.0 wt% SiB6 addition, the flexural strength of the samples at room temperature was enhanced from 6.75 MPa to 14.63 MPa due to the sintering promotion of oxidation product B2O3, and the flexural strength at 1550 °C was improved from 7.68 MPa to 13.08 MPa because of the enhanced β-cristobalite content, which is suitable for high temperature casting of ceramic cores. Therefore, it demonstrates the capability of fabricating SiB6 reinforced silica-based ceramic cores with high performance via stereolithography.