X‐ray Diffraction Study of the Structure of Silicon Nitride Fiber Made from Perhydropolysilazane

Continuous stoichiometric silicon nitride fiber was produced by the pyrolysis of perhydropolysilazane. This high‐purity silicon nitride fiber is colorless and has high strength, modulus of elasticity, and thermal stability which are properties suitable for reinforcing plastics, metals, glasses, and even ceramics. The structures of three kinds of amorphous silicon nitride fibers (with stoichiometric, Si‐excess and O‐excess composition) were investigated by X‐ray diffraction followed by calculating the radial distribution functions. Radial distribution functions were calculated from several possible crystal structures and compared with observed radial distribution functions.