Effect of different sintering additives type on Vat photopolymerization 3D printing of Al2O3 ceramics

Abstract

The mechanical properties of 3D printed alumina ceramics are degraded due to the micro anisotropy, interlayer interface defects and microporous characteristics. In order to improve its mechanical properties, solid phase sintered, liquid phase sintered and solid-liquid phase sintered alumina (Al2O3) ceramics were prepared by Vat photopolymerization 3D printing technology, respectively. In the experiment, Al2O3 was used as the main material to study the effects of TiO2 solid phase additive, MgO-SiO2 liquid phase additives and TiO2-MgO-SiO2 solid-liquid phase additives on Al2O3 ceramics sintering behavior and mechanical properties, so as to improve the sintering density and mechanical properties of alumina ceramics. The best composition ratio and sintering temperature were determined by shrinkage, relative density, Raman, XRD and SEM characterization. Under optimal sintering conditions, The comprehensive properties of Al2O3 ceramics prepared by liquid phase sintering are more balanced. And has excellent mechanical properties. The flexural strength reached 317 ± 34 MPa and the Vickers hardness up to 1250 ± 102 HV30. Thus, nine types of truss structures are prepared to study their mechanical properties. By changing the structure types, the order of compressive strength is FCC > BCC > DLS. By changing the number of units, the order of compressive strength is 3 × 3 × 3 units >2 × 2 × 2 units >1 × 1 × 1 units. The Al2O3 ceramics prepared by the liquid phase sintering exhibit excellent mechanical compression properties and energy absorption capacity. The FCC structure of 3 × 3 × 3 units can reach 23.2 ± 1.7 MPa compressive strength.