Novel amorphous polymer-derived Si-Hf-N ceramics were prepared via ammonolysis of single-source precursors which were synthesized by the chemical reaction of a commercially available perhydropolysilazane (PHPS) with different amounts of tetrakis(dimethylamido) hafnium(IV) (TDMAH). The prepared Si-Hf-N materials were annealed in nitrogen atmosphere at different temperatures ranging from 1100°C to 1800°C and investigated with respect to their chemical composition, crystallization behavior and phase evolution. The single-source precursors converted upon heat treatment in ammonia environment at 1000°C into amorphous single-phase ceramics and remained amorphous even after annealing at 1400°C in nitrogen atmosphere. Electron microscopy investigation showed that the annealing of the highly homogeneous single-phase Si-Hf-N induces local enrichment (clustering) of Hf, leading to amorphous HfN/SiNx nanocomposites. Annealing in nitrogen at 1600°C leads to the crystallization of HfN and Si3N4. The results of the present work emphasize a convenient preparative access to silicon-metal-nitride nanocomposites from suitable single-source precursors.
|ジャーナル||Journal of the European Ceramic Society|
|出版ステータス||Published - 2015|
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