蔗糖调控下采用冰冻铸造法制备多孔陶瓷的微观组织与力学性能

Porous Al₂O₃ ceramics were prepared by a self-designed directional solidification device based on the freeze-casting principle. The effect of sucrose content on the microstructures of porous ceramics was investigated. The results show that sucrose can change the faceted growth of ice crystals into non-faceted growth and the layered porous structure into cellular porous structure. The microstructures of porous ceramics gradually change from lamellar to cellular with the increase of sucrose content, and the compressive strength of the samples firstly increases and then decreases. The compressive strength increases from 18.90 to 22.24 MPa as sucrose content is increased from 0%(mass fraction) to 1%, and the maximum strength, 25.87 MPa, is obtained when sucrose content is 5%, and then the compressive strength decreases from 22.42 to 21.32 MPa when sucrose content is decreased from 7.5% to 10.0%. The mechanism is that the number of ceramic bridges in the layered porous structure increases, leading to the increase of the compressive strength, and there are regional boundaries between the cellular porous region and the lamellar porous region, and the boundaries can effectively obstruct the propagation of the crack between different regions when sucrose content increases from 0% to 5%.