Preparation of low shrinkage and high surface accuracy Al2O3-based ceramics via water-based binder jetting combined with sintering aid

The binder jetting method possesses the advantages of high efficiency and low cost, and is widely used in the preparation of ceramics. However, this technology uses organic binders, which leads to the low strength of ceramic green bodies after sintering. Currently, impregnation is primarily used to enhance the strength of ceramics. In this study, the properties of Al₂O₃-based ceramics were enhanced by introducing different minerals (kyanite, andalusite and sillimanite) that decompose and form a mullite phase at high temperatures, resulting in a secondary mullite reaction. The results show that when andalusite was added to the Al₂O₃ matrix material, the samples exhibited relatively good properties. The samples with different andalusite contents (5, 10, 15 wt%) were sintered at 1500, 1550 and 1600 °C, respectively. The bulk density, apparent porosity and bending strength of the samples were 1.82–2.06 g·cm⁻³, 47.5–52.01 % and 16.99–34.19 MPa, respectively.