DONG Lei, CHEN Yongjun, LUO Lijie, LI Hao, LI Tianfeng
(Key Lab of Advanced Materials of Tropical Island Resources of Ministry of Education, College of Materials and Chemical Engineering, Hainan University, Haikou 570228, Hainan, China)

Abstract: Freeze casting is a novel processing method to fabricate porous mullite ceramics built by mullite whiskers. Mullite whiskers were first prepared by heating raw materials of Al(OH)₃, SiO₂ and additives of AlF₃ and V₂O₅ at 1300°C. Then mullite whiskers were mixed with La₂O₃ and polyvinyl alcohol to prepare aqueous ceramic slurry. Finally porous mullite ceramics were fabricated by freeze casting method. The porous mullite ceramics show whisker-interlocked pore structure. The porosity of the ceramics is up to 88%, and can be tuned by changing the solid loadings of ceramic slurry. The porous ceramics also show good compressive strength due to the whisker-interlocked structure.

Key words: mullite; freeze casting; high porosity; whisker