摘要
通过X射线衍射仪和扫描电镜对高温处理后的纤维样品进行微观观察,发现随着热处理温度的升高,莫来石纤维的晶粒不断长大的同时,晶粒形貌也发生不同的变化。直径为5350nm的原始纤维其内部晶粒平均尺寸为60.5nm;1500℃热处理后的纤维表面晶粒从不规则粒状生长成形状规则的多面体状,测量的平均粒径为480nm,晶粒表面有台阶出现;1600℃热处理后的纤维直径为4160nm,表面晶粒形状由粒状变成垂直于纤维径向排列的片状,径向尺寸平均达1330nm,晶粒表面台阶轮廓更为清晰;此外,纤维内部在热处理过程中有气孔产生和消失的过程,1200℃煅烧后的纤维中有尺寸极小的小气孔生成,1300℃煅烧后可见有平均尺寸为60nm的小气孔,1500℃煅烧后气孔基本消失。莫来石纤维内部的大量空位聚集,导致纤维内部产生可见的气孔,另一方面,空位向表面运动又使纤维内部气孔消失,纤维产生自致密化,纤维表面的颗粒形成塔状阶梯。
The phase and microstructure of Mullite fiber sample were analyzed by X-ray diffraction （XRD） and scanning electronic microscope （SEM）. It is found that fiber after high temperature treatment gains size became larger while the gain morphology changed at the same time. The grain size of the origin fiber with diameter 5.35 μm was 60.5 nm. After being treated at 1500 ℃, the gains on fibers surface transformed from irregular granular to regular polyhedral, whose size was 0.48 μm, and some sidesteps occurred on these gains surface. After the fibers being treated at 1600 ℃, fibers diameters changed to 4.16 μm and the surfaces gains changed from granular to sheet-like, and arranged vertically along the radial of fibers, with sheet length 1.33 μm and the figure of the sidesteps becoming more clearly. In addition, some pores came into being and disappeared in fibers when sintered at different temperatures. Some very small pores could be seen after treated at 1200 ℃. Then the small pore size became 60 nm in the fiber treated at 1300 ℃. At last, the pore was became very small again and fell away when sintered at 1500 ℃. Lots of vacancies clustered in the mullite fiber, resulting in visible pores. On the other hand, the vacancies moved to the surface causing the pores disappearing. So the fibers became self-densification and the particles on the surface formed to be tower-like step shape.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2007年第A01期298-301,共4页
Rare Metal Materials and Engineering
关键词
莫来石纤维
显微结构
高温处理
mullite fiber
micrograph
high temperature treatment
