Effect of sintering aid combined vacuum infiltration on the properties of Al2O3-based ceramics via binder jetting

Binder Jetting (BJ) technology enables cost-effective and efficient fabrication of complex Al2O3-based ceramic components. However, in the process of manufacturing Al2O3-based ceramics using BJ, issues such as high sintering temperatures and relatively low sintered strength and relative density are encountered. In this study, we investigated the MnO2 sintering aid in combination with TiO2 sol-gel vacuum infiltration to introduce a MnO-TiO2-Al2O3 ternary sintering system, which could reduce the sintering temperature and enhance the strength and relative density of Al2O3-based ceramics. Through single-factor and response surface experiments, the effects of MnO2 addition, green body sintering temperature, infiltration time, and infiltration vacuum level on the properties and reinforcement mechanism of BJ Al2O3-based ceramics were studied. The research results revealed that with 10% MnO2 addition, a sintering temperature of 1450 °C, infiltration time of 60 s, and infiltration vacuum level of 24 KPa, the bending strength and sintered relative density of Al2O3-based ceramics reached 113.79 MPa and 78.13%, respectively. The bending strength was 48 times higher than that of the Al2O3 ceramic samples without sintering aid composite infiltration treatment, and the sintered relative density was improved by 41.85%.