Preparation and characterization of UV curable Al2O3 suspensions applying for stereolithography 3D printing ceramic microcomponent

The aim of this work is to develop a high solid loading suspension of Al2O3 dispersed in an UV curable acrylic based resin, suitable for SLA-3D printing micro-components with complex shapes. Silane coupling agents KH550, KH560 and the stearic acid (SA) were investigated as the surfactants for Al2O3 particles, and the low viscosity acrylic monomers ACMO, HDDA and NPG2PODA were used as the reactive diluents for Di-TMPTA-based premixed resins. The modified Al2O3 powders exhibit the different wettability with premixed resins to cause the different rheology behaviors among the formulated suspensions. The KH560-modified Al2O3 powders show the better wettability performance with NPG2PODA/Di-TMPTA-based solvents and their corresponding 75 wt% Al2O3 suspensions (44.2 vol% solid loading) with a viscosity ˂ 25,000 mPa·s at 30 s−1 shear rate are successfully prepared. The further analyses approve that hydrophobic structures of KH560 molecules have been introduced on the surfaces of Al2O3 powders. This consequence results in the lowest sediment rate and contact angle between the KH560-modified Al2O3 powders and NPG2PODA/Di-TMPTA-based resins, which contributes to their better wettability performance. The optimum parameter of NPG2PODA concentration of prepared suspension is range from 50% to 70% in the premixed resin. Finally, Al2O3 ceramic micro-component with 99.5% density was fabricated via an SLA process and subsequent sintering. Both the Al2O3 suspensions and sintered micro-components exhibit good homogeneous microstructures, indicating an optimistic dispersal uniformity of KH560-modified Al2O3 particles in the premixed resins.