Polymer precursor synthesis of novel ZrC–SiC ultrahigh-temperature ceramics and modulation of their molecular structure

Synthesis and pyrolysis of Hf–N–B backbone polymer precursor for HfC/HfB2 composite ceramics

“…Nowadays, the polymer-derived ceramics route is attracting increasing attentions for preparing UHTCs with tailored phase composition and microstructure. [11][12][13] Generally, the polymer precursors for Hf-based composite ceramics were synthesized using three methods, including the blending of Hf-containing polymers with Si-containing polymers, the grafting of Hf-containing compounds onto the side chain of Si-containing polymers, and the direct polymerization of Hf-N or Hf-C bonds as the main chain functioning as oxygen-free single-source precursors. For example, Zhang et al 14 prepared Hf-based SiBCN ceramics by pyrolyzing the blending precursors of polyborosilazane and polyhafnoxane, whereas Song et al 15 described a hafnium-containing polyborosilazane precursor for SiBCNHf nanocomposites by the reaction of polyborosilazane with Hf(N(Et) 2 ) 4 .…”

“…Most cases of the abovementioned powder methods require high‐temperature and high‐pressure operations; moreover, achieving a homogeneous composition and microstructure in composite ceramics is challenging due to the difficulties in dispersing raw powders. Nowadays, the polymer‐derived ceramics route is attracting increasing attentions for preparing UHTCs with tailored phase composition and microstructure 11–13 …”