INTERFACE CHARACTERIZATION OF NANOSIZED B-DOPED SI3N4 SIC CERAMICS/

Recent results on the crystallization behaviour of nanosized boron-dop ed silicon carbonitride ceramics as revealed by structural characteriz ation with various transmission electron microscopy methods are descri bed. Ceramic composites in the quaternary system Si-C-N-B were produce d by polymer pyrolysis of doped polysilazanes without the presence of oxide sintering additives. Annealing at elevated temperatures induces the crystallization of the initially amorphous materials, resulting in a microstructure consisting of nanocrystalline Si3N4, SiC and turbost ratic BN(C). Attention is focused on the BN(C) interface layers and th e lattice structure of the small-scaled crystallites in these nanocrys talline ceramics.