Fabrication of β-Si3N4 Fibers and Columan Cystals
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摘要: 采用燃燒合成工藝,制取了細長的β-Si3N4纖維·纖維頂端有小球,小球中含Si,Al成分,纖維有扭曲、擰結現象.VLS機制是控制纖維生長的主要機制.晶體頂端有螺旋生長蜷線.燃燒合成的β-Si3N4為六方柱晶,表面無缺陷。柱晶主要通過VC機制生長。β-Si3N4柱晶是從微晶β-Si3N4中長出的,其生長具有晶格繼承性.異相添加劑和少量雜質Al的引入有利于形成較長的柱晶和纖維。控制原始反應物中的添加劑含量,保持較高的燃燒溫度,是制取β-Si3N4纖維的關鍵。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.
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Key words:
- β-Si3N4 fibers /
- combustion synthesis /
- VLS /
- VC growth mechanism
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