Fabrication of the SiOC/HfO_2 Ceramic Composites by the Sol-Gel Method

摘要

In this paper, Hf element was introduced into the Si-O-C network by the sol-gel method using the dimethyldiethoxysiloxane (DMDES, (CH_3)_2Si(OC_2H_5)_2) and hafnium tetra(n-butoxide) (HfOR, Hf(OC_4H_9)_4) as raw materials. The SiOC/HfO_2 ceramic composite was obtained by pyrolyzing Si-Hf-O-C gel at 1000 °C in argon and the ceramics yield was 42.1 wt.%. FT-IR spectra revealed the presence of Si-O-Hf peaks at 932 cm~(-1). The weight loss of the as-prepared SiOC/HfO_2 was about 0.2 wt.% under argon atmorsphere up to 1550 °C, which was much lower than the hafnia-free SiOC composites and exhibited remarkable improved thermal stability.