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Short silicon nitride fibers were fabricated by direct nitridation of ferrosilicon in N2 atmosphere, and their structure and possible growth mechanism were characterized and investigated. The rod-like fibers which were α-Si3N4 with a low degree of crystallization and a high aspect ratio had a diameter of about 4 μm and a length close to a few millimeters. Belt-like fibers with a width about 5 μm and a thickness about 1 μm were also found in the nitrides. Scanning electron microscope (SEM), transmission electron microscope (TEM), high resolution transmission electron microscope (HRTEM), and selected area electron diffraction (SAED) investigations indicated that the fibers were single-crystalline α-Si3N4 with few amorphous distributed in the edge region, and the fibers grew by vapor–liquid–solid (VLS) mechanism.

Laminated (SiCw+SiCp)/SiC ceramic composites were fabricated by tape casting and chemical vapor infiltration (CVI), and the effect of SiC particles on strengthening/toughening of the composites was investigated. When the SiC particle content was constant, the mechanical properties of (SiCw+SiCp)/SiC composites were increased with increasing SiC whisker content. When the SiC particle content was varied, the mechanical properties of (SiCw+SiCp)/SiC composites were dependent on SiC particle content. The addition of SiC particles can increase the strength of the matrix and the crack propagation resistance, the former increased the strength and the latter increased the toughness.

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