Pressureless Sintering of B4C-TiB2 Ceramic Composites

Pressureless sintering of the B 4 C ceramics containing 0-25 vol.% TiB 2 phase was studied in the isothermal and constant heating rate regimes. The B 4 C-TiB 2 composites were pressureless sintered to a relative density of 97.5% at 2100°C. It was found that the heating rate had no visible effect on the density. A new approach to the constant heating rate analysis taking into account the coarsening kinetics was developed. It was shown that the sintering process is controlled by coarsening of TiB 2 particles as well as by grain boundary diffusion. The effective activation energy for sintering was estimated. The isothermal microstructural evolution at the final stage of sintering was discussed.