摘要
针对自蔓延制备氮化硅过程迅速,但可控性差的问题,研究了氮化硅晶粒在自蔓延中的生长过程及一些特殊形状晶粒形成的原因.通过设计累积试验、借助扫描电镜观察粉体形貌、讨论分析氮化硅α相和β相形成机理说明,颗粒有限长大是生长和分解达到平衡后实现的,波浪形和凹面状颗粒是晶粒在类似液相烧结和固相烧结共同作用下产生的,"树杈"状颗粒是β相氮化硅在氮化硅"籽晶"上生长和液相烧结作用下形成的.研究表明,要减小自蔓延制备氮化硅粉体的粒度、阻碍颗粒异常长大,需要合理控制稀释剂比例,降低反应温度.
The reaction speed during self-propagating high-temperature synthesis （SHS） of Si3N4 powder is too fast to be controlled, so that the growth mechanism of Si3N4 powder prepared by SHS is obscure. In order to clarify the growth mechanism of Si3N4 powder by SHS and the formation causes of some grains with particular shape, the growth course of α-Si3N4 and β-Si3N4 was investigated by cumulative experiment and the morphology of the powder was observed using SEM. The results reveal that the limited growth of the grains is realized after reaching the balance in growth and decomposition of the grains. The wavy and concave grains form under the combined action of similar liquid phase and solid phase sintering. The crotch-like grains results from both the growth of β-Si3 N4 on the seed crystal and liquid phase sintering. The reasonable control of diluent ratio and the decrease of reaction temperature can reduce the grain size of Si3N4 powder prepared by SHS and impede the abnormal growth of Si3N4 grains.
出处
《沈阳工业大学学报》
EI
CAS
2009年第2期186-190,共5页
Journal of Shenyang University of Technology
关键词
氮化硅
自蔓延
稀释剂
形成机理
长大方式
silicon nitride
self-propagating high-temperature synthesis
diluent
growth mechanism
growth mode
