Abstract: β-Si₃N₄ rod-like crystals were fabricated under high nitrogen pressure by using the Self-propagating High-temperature Synthesis method. The
effect of different amount of Y₂O₃ addition on the aspect ratio of β-Si₃N₄ rod-like crystals was studied. By using copper crucible absorbing the heat generated
by the exothermic reaction to quench the reaction, the growth morphology of β-Si₃N₄ in the different stages of the reaction was observed. The reaction courses were
also expounded. The results reveal that the optimum amount of Y₂O₃ addition is 2wt%～5wt%. Too much amount of Y₂O₃ addition could result in the
inhomogeneous growth and distribution of the crystals. By considering the morphology of the products, the growth mechanisms of β-Si₃N₄ rod-like crystal
are the results from the synergy of the VLS and VS.

Key words: self-propagating high temperature synthesis, β-silicon nitride, rod-like crystal, growth mechanism