Effect of debinding temperature under an argon atmosphere on the microstructure and properties of 3D-printed alumina ceramics

Debinding at different temperatures under an argon atmosphere, combined with sintering, was used to obtain alumina ceramics fabricated from stereolithography-based 3D printing. The effect of debinding temperature under an argon atmosphere on the microstructure, physical, and mechanical properties were investigated. The results showed that the alumina ceramics had a layered structure, and the interlayer spacing first increased and then decreased with the debinding temperature. Some carbon residue was observed when debinding was performed between 350 and 450 °C, and no residual carbon was observed when the debinding temperature was higher than 500 °C. The shrinkage in the Z direction was much greater than that of the X or Y directions due to layer-by-layer forming mode. There was a slight fluctuation in mechanical properties such as flexural strength (18.9–22.3 MPa), Vickers hardness (110.6–173.7 HV), and nano-indentation hardness (16.9–22.6 GPa). The optimal debinding temperature was 500 °C under an argon atmosphere, which displayed a shrinkage of 2.3% in the X direction, 1.9% in the Y direction, and 3.4% in the Z direction. At this temperature, the flexural strength of the ceramics was 22.3 MPa and the open porosity of the ceramics was 35.6%.