【摘要】 采用自蔓延高温合成（SHS）,在高压氮气中成功地合成了β-Si3N4棒晶,研究了添加不同量Y2O3对自蔓延燃烧合成β-Si3N4。棒晶长径比的影响.结果表明,Y2O3添加量有一个最佳范围,当Y2O3的添加量在2Wt％～5wt％时,棒晶生长均匀,长径比约为8.通过铜坩埚吸热淬火的方法,观察到β-Si3N4棒晶不同生长阶段的显微形貌,从而推测其生长机理为VLS和VS两种机理协同作用的结果.本文对β-Si3N4棒晶生长的反应历程也进行了阐述.更多还原

【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.更多还原