摘要
用高分辨电镜观察了热压氮化硅中β相晶体生长界面的结构特点,用链柱结构描述并比较了α和β氮化硅晶体结构的异同,指出了β氮化硅晶体在α氮化硅品格中生长可以通过部分原子的迁移实现。添加剂离子进入第二类α链柱中大的间隙及在c轴方向的优先扩散,促进第二类链柱的转变。生长过程中某个β(100)晶面组可以先形成。出现二维有序的过渡性溶胀状态,同时进一步促使β晶粒呈细长柱状生长。从同一α晶体中生长的β晶体具有完全相同取向时,容易在棱柱面方向聚结。当β氮化硅与M-Si-O-N液相接触,螺线生长机制起主要作用。
Interface structure related to growth of β- Si_3N_4 in hot pressed silicon nitride was observed by high resolution electron microscopy (HREM). Compared the structure of α-Si_3N_4 crystal with β-Si_3N_4 crystal in the chain columns consisting of SiN_4 tetrahedron chains, considering possible behaviour of additive ions and property of chemical bonds possibly formed in α-Si_3N_4, it is suggested that, in the early period of dissolution, the first kind of chain column of α-Si_3N_4 may preferentially transform to β-chain column and a group of (100) planes is formed firstly through metal cations entering into large interstitial sites in α-Si_3N_4, and some Si+N→Al+O substitution and preferred diffusion occur in direction of c-axis where ordering in two dimensions may occur. This is the main reason why β- Si_3N_4 crystals grow anisotropically. When α-Si_3N_4 dissolve more sufficiently, the spiral growth machanism will play a more importent role in the growth prosses of β-Si_3N_4 crystal.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
1993年第5期393-398,共6页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金
关键词
氮化硅
晶体生长
电镜
热压
陶瓷
silicon nitride
crystal growth
high resolution electron microscopy
