Kinetic effect of boron on the crystallization of Si3 N4 in Si-B-C-N polymer-derived ceramics

摘要: The amorphous Si–B–C–N ceramics with a similar Si/C/N atomic ratio and various boron contents of 3.7 6.0 at.% B were synthesized then isothermally annealed at temperatures ranging from 1550 to 1775 °C. course crystallization for the modifications Si3N4 was examined by quantitative analysis corresponding x-ray diffraction patterns. Additionally, recent results investigations on ceramic 8.3 also considered. kinetic demonstrates that controlling mechanisms crystallization, continuous nucleation diffusion-controlled growth, are independent content. Nevertheless, estimated activation energy significantly increases 7.8 11.5 eV amount at.%. It is concluded role in kinetics mainly due effect process. Beside analysis, correlation between content crystallite size has been discussed.