A novel HfSiO wire drawing phenomenon after ablation of SiCnws/HfCSiC coating on C/C composites

Abstract

A SiCnws/HfCSiC coating was fabricated by a two-step chemical vapor deposition. After introducing SiC nanowires, the fracture toughness of HfCSiC coating increases by 228%. After ablation under oxyacetylene torch for 60s, a bone-like HfO2 reticular structure was formed in the central ablation area. Interestingly, a novel HfSiO wire-drawing phenomenon was happened in the transition area of ablated SiCnws/HfCSiC coating, providing a new toughness mechanism under ablation environment. Moreover, HfO2 precipitated from HfSiO glass wires to generate nanocrystalline grains during ablation, which explains the formation of bone-like HfO2 reticular structure observed from central ablation area. Keywords: Ultrahigh temperature ceramic, Coating, Drawing wires, Nanocrystalline grains, Mechanical properties