3D Printing Of Alumina Ceramics Through Digital Light Processing

As one of the most stable substances in solid metal oxides,alumina ceramics are the most widely used ceramic materials in oxide ceramics.However,alumina ceramic materials have poor processability and are often faced with complicated manufacturing processes,high difficulty and high cost in the manufacture of complex models.In this study,the Digital Light Projection(DLP)3D printing technology was used to prepare alumina ceramic bodies which can reduce manufacturing costs,shorten manufacturing cycle and improve efficiency.Different kinds of dispersing agents were studied in the experiment.It was found that the low molecular weight copolymer(BYK111)containing acidic groups had the best dispersion effect on the A12O3 ceramic slurry.The ceramic slurry with 2.5 wt.%solid content had the lowest viscosity.When the concentration of the photoinitiator 2,4,6-trimethylbenzoyldiphenyl-phosphine oxide(TPO)was 1wt.%,the ceramic slurry had reasonable curing depth and expanded width.With the increase of A12O3 solid volume fraction(40,45,50,54 vol.%)in the ceramic slurry,the curing depth reduced,the expanded width increased at the same exposure intensity and the viscosity of the slurry also increased.The slurries were used as raw materials for DLP 3D printing of Al2O3 green bodies.According to the TG/DSC curve of the degreasing process,a reasonable thermal degreasing heating system was established,and dense A12O3 ceramics were obtained by high-temperature sintering.With the increase of the volume fraction of A12O3 in the ceramic slurry,the linear shrinkage of the sintered ceramics gradually decreased,the Vickers hardness increased,and the density increased.When the solid volume fraction of Al2O3 was 54 vol.%,the sintered ceramics had a Vickers hardness of 1533 HV and a density of 99.1%.Some common defects such as dead pores have been found in the sintered ceramics by the microscopic morphology analysis.Finally,porous ceramics with complex three-cycle minimal surfaces were printed using alumina slurries with 50 vol.%solid content..After sintering,the ceramic surfaces were smooth and crack-free,and the curved surfaces were smooth and continuous with good pore connectivity.