Fabrication and characterization of Short silicon nitride fibers from direct nitridation of ferrosilicon in N₂ atmosphere

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.