Production of HfB2-SiC (10-65 vol % SiC) Ultra-High-Temperature Ceramics by Hot Pressing of HfB2-(SiO2-C) Composite Powder Synthesized by the Sol-Gel Method

摘要

The formation of HfB2-SiC (10-65 vol % SiC) ultra-high-temperature ceramics by hot pressing of HfB2-(SiO2-C) composite powder synthesized by the sol-gel method was studied. By the example of HfB2-30 vol % SiC ceramic, it was shown that the synthesis of nanocrystalline silicon carbide is completed at temperatures of as low as aeyen1700A degrees C (crystallite size 35-39 nm). The production of the composite materials with various contents of fine silicon carbide at 1800A degrees C demonstrated that the samples of the composition HfB2-SiC (20-30 vol % SiC) are characterized by the formation of SiC crystallites of the minimum sizes (36-38 nm), by the highest density (89%), and by higher oxidation resistance during heating in an air flow to 1400A degrees C.