Significant Improvement of Mechanical Properties of SiC-Nanowire-Reinforced SiC(f)/SiC Composites via Atomic Deposition of Ni Catalysts

This study aimed to study the effects of different catalyst introduction methods on the distribution of SiC nanowires (SiCNWs) and the mechanical properties of SiC(f)/SiC composites. Two different catalyst-introduction methods (electroplating (EP) vs. atomic deposition (AD)) have been used to catalyze the growth of SiC nanowires in SiC(f) preforms. The morphology, structure and phase composition were systematically investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The SiCNWs-reinforced SiC(f)/SiC composited was densified by CVI. The compressive strength of the SiCNWs-reinforced SiC(f)/SiC composites was evaluated by radial crushing test. Compared with EP, atomic Ni catalysts fabricated by AD have higher diffusivity for better diffusion into the SiC(f) preform. The yield of SiCNWs is effectively increased in the internal pores of the SiC(f) preform, and a denser network forms. Therefore, the mechanical properties of SiCNW-containing SiC(f)/SiC composites are significantly improved. Compared with the EP-composites and SiC(f)/SiC composites, the compressive strength of AD-composites is increased by 51.1% and 56.0%, respectively. The results demonstrate that the use of AD method to grow SiCNWs is promising for enhancing the mechanical properties of SiC(f)/SiC composites.