ALATENG Shaga, CHEN Xing, CHEN Guanhong

(School of Materials Science and Engineering, Jilin Jianzhu University, Changchun 130117, Jilin, China)

Abstract: Bio-inspired SiC porous ceramics with gradient lamellar structure were prepared by using unidirectional thermostatic freeze casting. The effects of initial solid content of water-based SiC ceramic slurry and freezing temperature on microstructure (including porosity, lamellar thickness and structural wavelength) and the compressive strength of the SiC porous ceramics were studied. With increasing distance from the cold end, the lamellar thickness and structural wavelength of the lamellar porous SiC scaffolds increased along the freezing direction. With increasing initial solid content (20 vol.%~40 vol.%), the porosity of the scaffolds decreased, the compressive strength, the lamellar thickness and the structural wavelength all increased, while the ranges were 10 μm~100 μm and 15 μm~140 μm, respectively. With decreasing freezing temperature, the structural wavelength and lamellar thickness of the scaffolds decreased, but the compressive strength increased. The thermostatic freeze casting is simple in operation, pore size distribution and porosity are adjustable, and it can be used to prepare materials with large size and complex shape.

Key words: freeze casting; gradient lamellar structure; SiC porous ceramics; microstructure; mechanical properties