An insight into the effects of epoxy coating agent and sintering temperature on vat photopolymerization-printed Al2O3 parts

As an additive manufacturing technology, vat photopolymerization (VPP) can print ceramic parts with high resolution and good surface quality at a low cost. Therefore, VPP has been widely used to process a variety of ceramic materials. Despite these benefits, it is still a challenge to fabricate defect-free ceramic parts owing to ceramic materials’ inherent brittleness and low toughness. To overcome these issues, two types of coating agents (i.e., E44 and E51 coating agents) are selected to coat alumina (Al2O3) parts by the authors. Experimental results show that the parts coated with the coating agents demonstrate fewer defects, better physical properties, and enhanced mechanical properties (including flexural and compressive properties), compared with the uncoated Al2O3 parts. Particularly, the average surface roughness of coated Al2O3 parts can be reduced from 2 μm to 35–180 nm. In addition, the absorbed energy can be increased by around 17% when E51 coating agent is adopted. To study stress distribution changes and strengthening and toughening mechanisms induced by the coating agents, finite element modeling analysis and molecular dynamic simulations have been performed.