β-Si3N4纤维及柱晶的制取

β-Si₃N₄纤维及柱晶的制取

摘要: 采用燃烧合成工艺，制取了细长的β-Si₃N₄纤维·纤维顶端有小球，小球中含Si，Al成分，纤维有扭曲、拧结现象.VLS机制是控制纤维生长的主要机制.晶体顶端有螺旋生长蜷线.燃烧合成的β-Si₃N₄为六方柱晶，表面无缺陷。柱晶主要通过VC机制生长。β-Si₃N₄柱晶是从微晶β-Si₃N₄中长出的，其生长具有晶格继承性.异相添加剂和少量杂质Al的引入有利于形成较长的柱晶和纤维。控制原始反应物中的添加剂含量，保持较高的燃烧温度，是制取β-Si₃N₄纤维的关键。

Abstract: β-Si₃N₄ fibers were fabricated through combustion synthesis （CS） process.Droplets composed of Si and Al at the tip of fibers were found. It is concluded that the growth of β-Si₃N₄ fibers is controled mainly by VLS mechanism. Hexagonal colummna single crystal β-Si₃N₄ with smooth surface and without any default was also found in the conbustion process of silicon powder. VC process is the controled mechanism for the growth of colummna single crystal β-Si₃N₄.