纳米SiC陶瓷的超高压烧结研究(英文)

以纳米SiC为原料,用两面项压机在不同工艺条件下(1 000～1 300℃,4.0～4.5 GPa,15～35 min)实现了40(质量分数,下同)Al2O3烧结助剂添加的SiC陶瓷体的烧结.研究了烧结工艺对SiC陶瓷性能的影响.用X射线衍射、扫描电镜、显微硬度测试仪等对SiC高压烧结体进行了表征.结果表明:Al2O3是有效的低温烧结助剂,在超高压工艺下添加4%Al2O3即可实现SiC陶瓷全致密化烧结;烧结体晶粒长大得到抑制,维持在纳米级,晶格常数收缩了约0.45%;烧结体显微硬度和密度随烧结温度、烧结压力的升高或保温时间的延长而提高.

FABRICATION OF SiC CERAMIC BY ULTRA-HIGH PRESSURE TECHNIQUE

A high density SiC ceramic with 4% (in mass, the same below) Al2O3 as a sintering additive was fabricated with SiC nano-particles as raw materials under different conditions (i.e., 1000-1 300℃, 4.0-4.5 Gpa, 15-35 min) using a two-face anvils press.The effects of sintering parameters on the mechanical properties of SiC ceramics were investigated. The SiC ceramic was character-ized by X-ray diffraction, scanning electronic microscopy, energy dispersive spectrometer and micro-hardness instrument. The results show that, the SiC mixture with only 4% Al2O3 can be sintered by a ultra-high pressure technique when Al2O3 is used as an effective sintering additive. The crystalline grain size of the SiC ceramic is in nano-scale, and its crystal lattice shrinkage is about 0.45%. Its micro-hardness and density increases with the increment of the sintering temperature, pressure and time.