3D printing of honeycomb Si3N4 ceramic

In this paper, a honeycomb Si3N4 ceramic was fabricated by 3D printing with a well-preserved structure. The effects of Si3N4 content on the rheological properties of Si3N4/sol-silica ink and the printing resolution of products were investigated. The microstructure, phase composition, liner shrinkage rate, and fracture behavior of printed samples before and after sintering were systematically characterized in detail. The results showed that the modified inks had the optimized rheological properties, and the stress-shear rate curves corresponding to each slurry could be well described by Bingham and Herschel-Bulkley fluid models. The corresponding slump rates of the printed samples with different Si3N4 to sol-silica mass ratios were all lower than 4%, and the linear shrinkage rate of all of the samples after sintering was below 20%. The fracture behavior under compressive loading of the honeycomb Si3N4 ceramics tended to be non-catastrophic fractures both before and after sintering. The compressive strengths of all of the printed samples decreased with the increase of the Si3N4 content, and the highest compressive strength of the honeycomb ceramics could reach 131.2 MPa after sintering at 1600 degrees C, which was about 366.9% higher than that of the samples in green state prior to the sintering.