Polycrystalline Nanograin Formation in Uniform-Sized Silicon Carbide Fibers Derived from Aluminum-Containing Polycarbosilane

The mobility of ion species is a critical factor for changes in crystal lattice of silicon carbides derived from polycarbosilane precursors. Here, we study the polycrystalline nanograins and their formations in silicon carbide fibers under different thermolysis conditions. We identify the rheological properties and fiber spinnability of aluminum-containing polycarbosilane precursors to elucidate the polymer networking, further polymerization, and structural rearrangement behaviors during the spinning process. The continuous and uniform jetting of the precursors is enabled within the preferable temperature ranges discovered by the storage and loss moduli plots. An enhanced network formation by further polymerization and structural rearrangement helps increase the formation of polycrystalline nanograins in the uniform-sized silicon carbide fibers.