Highly Ordered Macroporous BN-Based Ceramics Prepared from Templated Preceramic Polymers
Macroporous SiCBN and BCN ceramic were prepared by infiltrating these preceramic polymers into the colloidal silica crystalline array, followed by pyrolysis at 1400ı and subsequently etching off the silica spheres. It is generally observed by SEM and TEM that a highly ordered and interconnected 'honeycomb' pore structure was obtained by replicating the three dimensional close packed silica spheres which was fabricated by natural sedimentation. And BET surface areas in range 413 ~ 315 m2/g and pore sizes of 113 ~ 395 nm in the porous materials were tailored by controlling the sacrificial silica sphere sizes in range 145~500 nm even under volume shrinkage involved during pyrolytic step. The porous SiCBN ceramics and BCN ceramic showed a slight weight loss of 0.2~0.8% and 4%, respectively, indicating excellent resistance to oxidation.
Hai-Doo Kim, Hua-Tay Lin and Michael J. Hoffmann
L. Y. Hong and D. P. Kim, "Highly Ordered Macroporous BN-Based Ceramics Prepared from Templated Preceramic Polymers ", Key Engineering Materials, Vol. 287, pp. 323-328, 2005