In-situ growth of SiC w on the surface of C/C composite materials and different influencing factors on the morphology control of SiC w transition layer

Abstract

The in-situ growth of SiC whisker (SiCw) buffer layer on the surface of C/C composite material substrates provides an excellent solution to alleviate the thermal stress mismatch with the oxidation-resistant coating. Nevertheless, the growth mechanism of SiCw on the surface of C/C composite materials has been a subject of ongoing debate. This study initially investigates the reduction process of Ni(NO3)2·6H2O as a catalyst precursor and analyzes the morphological impact of Ni nanoparticles on the surface of C/C composite materials with respect to SiCw. Furthermore, it summarizes the V-L-S growth mechanism and V-S mechanism of SiCw, providing a comprehensive analysis of the microstructure and defects associated with SiCw growth under different mechanisms. The catalytic mechanism of Ni particles and the role of twinning and Z-shaped dipoles in whisker growth are elucidated. Finally, the influence of temperature and time on whisker morphology is examined, with particular emphasis on the occurrence of bead-like whiskers. This research extensively elucidates the growth process of SiCw on C/C composite substrate, resolving the previously ambiguous growth mechanism through structural analysis under diverse conditions.