采用高温等静压（HIP）工艺，制备了纳米结构的单相SiC及Si3N4／SiC复相陶瓷，并通过X射线衍射分析、透射及高分辨电镜对其相组成及结构进行了表征．实验表明，在温度1850℃、压力200MPa条件下保温lh，可获得晶粒尺寸＜100nm、结构均匀、致密的单相SiC纳米结构陶瓷．对于Si3N4／SiC复相体系，初始粉末的结晶形态对烧结体的结构有很大的影响.将初始粉末进行预处理后：在温度1750℃、压力150MPa条件下保温1h，可获得晶粒尺寸在50nm左右、结构致密、均匀的复相Si3N4／SiC纳米陶瓷材料．
Hot isostatically pressed nano-ceramics of monophasic SiC and Si3N4/SiC composite were studied,and the phase composition and ndcrostructure were characterized by XRD, TEM and HREM. It is skownthat fine and homogeneous microstructure with average grch size of less than 100nm for monopkasic SiC can be obtained at the HIP conditions of 1850°C, 200MPa for 1h. The starting powder materialssignificantly affect the final microstructure. At 1750°C, 150MPa for 1h, very fine and homogeneous mi-crostructure with the average grain size of about 50nm can be prepared by using the pretreated composed Si3N4-SiC nano-powder. Both of the different phase compositions of nano-powder and HIP conditions may be ascribed to the depression of grain growth.
参考文献
| [1] |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%