Article ID Journal Published Year Pages File Type
7990669 Journal of Alloys and Compounds 2018 31 Pages PDF
Abstract
Precursors with different nitrogen contents were synthesised using hafnium (IV) chloride (HfCl4), dicyandiamide (DICY) and triethylamine (Et3N) as raw materials and were used for preparing Hf-based nanocomposites. The synthesis, ceramic conversion and microstructural evolution of HfC-based nanocomposites derived from precursors with different nitrogen contents were investigated. The results indicate that the composition of the synthesised precursors can be controlled by adjusting the molar ratio of HfCl4 and dicyandiamide. Pyrolysis of the precursors at 1200 °C led to the formation of Hf2CN or HfN-based ceramics. As the nitrogen content of the synthesised precursors increased, the Hf2CN crystallites present in the ceramics annealed at 1200 °C gradually transformed to HfN. Furthermore, at 1600 °C, the HfN and Hf2CN phases gradually converted to HfC(N). The results also indicate that nitrogen favours the sintering of the obtained nanocomposites. The HfC-based ceramics should be promising for application as high-performance composite ceramics.
Related Topics
Physical Sciences and Engineering Materials Science Metals and Alloys
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