Infiltration of silica slurry into silica-based ceramic cores prepared by selective laser sintering based on pre-sintering

Abstract

The silica-based ceramic core is an important mold for manufacturing hollow blades. The preparation of silica-based ceramic cores by combining selective laser sintering (SLS) and vacuum infiltration (VI) technologies is a promising approach. To enhance infiltration effect, pre-sintering was introduced to obtain the bodies with high porosity and hydrophilicity. The infiltrated silica content increased from 29.58 wt% for samples infiltrated once to 68.91 wt% for samples infiltrated three times. The increase of silica content in the matrix reduced the porosity of final ceramics, thus improving the room-temperature flexural strength. The infiltrated silica gradually transformed into cristobalite during the high-temperature test, which improved the high-temperature flexural strength and creep resistance. When the final-sintering temperature was 1225 °C, room-temperature and high-temperature flexural strength reached 21.17 MPa and 21.21 MPa, respectively, due to the enhanced sintering necks and low porosity. These results indicate that our work provides a promising route to fabricate silica-based ceramic cores by SLS technology.