摘要
借助两面顶超高压设备,通过冷等静压和超高压成型制备了相对致密度>60%的SiC陶瓷生体。在低压流动氮气保护下,无压烧结获得了晶粒尺寸在200nm左右的高致密的SiC陶瓷。利用扫描电镜、X射线衍射对烧结体的断面形貌和相组分进行分析。结果表明:超高压处理能够提高坯体及烧结体的致密度,并有助于抑制晶粒的长大。添加12%烧结助剂[Al2O3(平均粒度约为80nm)和Y2O3(平均粒度约为50nm)],经4.5GPa,6min超高压成型的SiC样品,在1850℃或1900℃烧结0.5h后的相对密度分别达到95.3%和98.3%。这种样品的烧结致密化机制为Y3Al5O12液相烧结。
SiC green bodies with relative density over 60% were prepared through cooling isostatic pressing and ultrahigh pressure compaction by a belt type apparatus. Dense SiC ceramics with grain size around 200 nm were prepared by pressureless sintering in flowing nitrogen gas. The fracture surface and composition of the sintered samples were analyzed by scanning electron microscopy and X-ray diffraction. The density of sintered body was improved and the grain growth was depressed by the ultrahigh pressure com- paction. The relative densities of the SiC samples with adding of 12% in mass sintering aids （Al2O3 powder with a average particle size of -80nm and Y203 powder with a average particle size of --50nm） after forming at 4.5 GPa for 6rain and sintered at 1 850℃ or 1900℃ for 0.5 h are 95.3% and 98.3% respectively. Sintering mechanism of the sample is Y3Al5O12 liquid phase sintering.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2008年第11期1629-1632,共4页
Journal of The Chinese Ceramic Society
基金
国防基础科研(A3120061156)资助项目
关键词
碳化硅
超高压成型
无压烧结
silicon carbide
ultrahigh pressure compaction
pressureless sintering
