Porous gelcasted and solid-state-sintered SiC (S-SiC) ceramics with significantly improved connectivity were successfully prepared through the synergistic pore-forming mechanism of direct foaming and particle packing, using fine (D 50 = 0.5 μm) and coarse (D 50 = 5.0 μm) graded SiC powders as the main raw materials. As the proportion of coarse SiC powder increased, the viscosities of aqueous SiC-B 4 C-C slurries sharply decreased, which thus flourished foaming and enlarged bubble-derived-pore diameter in porous S-SiC ceramics, accompanied with the increased amount and size of window. Moreover, abundant particle-packing pores in struts of bubble-derived pores were also formed and even interconnected with each other at 60 wt% of coarse SiC powder. Besides, there was a remarkable increase in porosity from 61.0% to 81.7% and accordingly a significant decline in density from 1.24 g cm −3 to 0.58 g cm −3 as the content of coarse SiC powder increased. The optimized multiple pore microstructures resulted in an amazing nitrogen gas permeability of 1.78×10 −11 m 2 under the condition of an excellent compressive strength of 10.8 ± 2.7 MPa.
Stereolithography based additive manufacturing provides an effective method to fabricate complex-shaped SiC ceramic components. The dispersion and stability of the ceramic slurry are very important for stereolithography. In this study, the dispersion and stability of SiC ceramic slurries were investigated systematically. The effects of resin monomers , dispersants , particle size, solid loading and ball milling time on the dispersion, rheological behavior and stability of SiC ceramic slurries were studied in detail. Finally, an optimal SiC ceramic slurry for stereolithography based additive manufacturing was obtained, and complex-shaped SiC ceramic architectures were fabricated.
危险品化学品经营许可证（带存储）