Indirect selective laser sintering of epoxy resin-Al_2O_3 ceramic powders combined with cold isostatic pressing

摘要

To fabricate Al_2O_3 ceramic components with complex shape, selective laser sintering (SLS) combined with cold isostatic pressing (CIP) process was used to consolidate Al_2O_3 powder with additive of epoxy resin E06 (ER06) and polyvinyl alcohol (PVA). The starting material preparation combined spray drying with mechanical mixing to formulate compound powder consisting of PVA (1.5 wt%), ER06 (8 wt%) and Al_2O_3 and provide a good fluidity for SLS. Experimental investigations were carried the shrinkage, relative density, bending strength of Al_2O_3-ER06 SLS specimens in order to optimize the laser sintering parameters. It was found that Al_2O_3-ER06 SLS specimens represented acceptable shrinkage, high density and bending strength when laser power, scanning speed, scanning space and layer thickness were, respectively, 21 W, 1600 mm/s, 100 μm and 150 μm. Following that, the SLS specimens were processed through CIP to eliminate the pores in green ceramics. Finally, the optimized SLS/CIP Al_2O_3 specimens were debinded, sintered to produce crack-free Al_2O_3 bodies. The final Al_2O_3 components achieved a relative high density of more than 92% after furnace sintering. The study shows a novel and promising approach to fabricate complex ceramic matrix and ceramic components via indirect SLS and CIP process.