Lightweight porous Al2O3-based ceramics with highly controllable performance via binder jetting

Abstract

This study introduces a feasible approach for preparing Al₂O₃-based ceramics with highly controllable performance via binder jetting. The Al₂O₃-based ceramics were prepared using Al₂O₃ and H₃BO₃ as raw materials. The results showed that the samples prepared with 0.24 mol H₃BO₃ exhibited high apparent porosity (64%–66.67%), well-bending strength (3.46–8.53 MPa), and low thermal conductivity (0.113–0.329 W·m⁻¹·k⁻¹ at 200–800°C). It was observed by an electron microscope that the increase of boric acid content led to the in-situ formation of more aluminum borate grains in the sample. Meanwhile, the remaining Al₂O₃ reacts with silicon oxide in the impregnation solution to form mullite whiskers. The whiskers ensured that the sample had superior mechanical properties and lower thermal conductivities. Based on the above properties, the possibility of Al₂O₃-based ceramics application in the aerospace field can be speculated.