Preparation of high-performance silica-based ceramic cores with B4C addition using selective laser sintering and SiO2–Al2O3 sol infiltration

Abstract

Silica-based ceramic cores are commonly employed to fabricate hollow aero-engine blades during investment casting. However, achieving excellent performance and high precision remains an extremely challenging problem. In this study, silica-based ceramic cores with boron carbide (B4C) addition were prepared by selective laser sintering (SLS) and SiO2–Al2O3 sol infiltration. The effects of B4C content and mass ratio of alumina to silica in the SiO2–Al2O3 sol on the mechanical properties of the obtained silica-based ceramic cores were explored. The results suggested that the room temperature flexural strength was gradually improved from 3.39 MPa to 27.35 MPa at B4C content from 0 to 2 wt% due to the oxidation of B4C, and the linear shrinkage gradually increased to 4.61%. Furthermore, the high temperature flexural strength was enhanced from 4.86 MPa (non-infiltrated) to 11.84 MPa at mass ratio from 0 to 1 because of the generated mullite phase and the linear shrinkage decreased to 1.38%, which can meet the application requirements for the preparation of ceramic cores. Consequently, it shows the capability to prepare high-performance silica-based ceramic cores with B4C addition by combining SLS technology and SiO2–Al2O3 sol infiltration process.