Colloidal processing and mechanical properties of silicon carbide with alumina
Colloidal processing and mechanical properties of silicon carbide with alumina
复制标题
碳化硅与氧化铝的胶体加工及机械性能
DOI：
10.1557/jmr.1997.0411
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发表时间：
1997
影响因子：
2.7
通讯作者：
S. Sameshima
中科院分区：
文献类型：
--
作者：
Y. Hirata;Kouji Hidaka;Hiroaki Matsumura;Y. Fukushige;S. Sameshima
SiO_2包覆0.4- 1.8wt%的亚微米SiC和α-Al_2O_3粉末（平均粒径0.2 μ m）在pH值3.0-10.0的水溶液中混合。SiC/Al_2O_3（4.3- 6.9wt. %）的粉末通过过滤通过石膏模具固结，并在1600 - 2040 °C下在39 MPa的压力下热压。在1700°-1800 °C下将这些压块致密化至接近理论密度。通过对SiC/Al_2O_3复合材料热压收缩曲线的分析，探讨了SiC/Al_2O_3复合材料的烧结机理。在1800 °C以下等轴SiC晶粒以低长径比长大，在1900 °C时转变为板状晶粒。SiC的断裂韧性与平均晶粒尺寸的函数关系在长径比为1 ~ 2的2.5 μ m晶粒处达到最大值5 Mpa · m^0.5。在室温下的弯曲强度为230-430 MPa的SiC理论密度的98%以上，并表现出类似的晶粒尺寸依赖性。
Submicrometer-sized SiC coated with SiO_2 of 0.4–1.8 wt.% and α–Al_2O_3 powder of median size 0.2 μ m were mixed in aqueous solutions in the pH range 3.0–10.0. The SiC/Al_2O_3 (4.3–6.9 wt. %) powders were consolidated by filtration through gypsum molds and hot-pressed at 1600°–2040 °C under a pressure of 39 MPa. These compacts were densified to near the theoretical density at 1700°–1800 °C. The sintering mechanisms are discussed based on the analysis of shrinkage curves of SiC/Al_2O_3 compacts during hot-pressing. The equiaxed SiC grains grew with low aspect ratios below 1800 °C and changed to plate-like grains at 1900 °C. The fracture toughness of SiC as a function of average grain size reached a maximum of 5 Mpa · m^0.5 at 2.5 μ m grains of low aspect ratios of 1–2. The flexural strengths at room temperature were 230–430 MPa in the SiC above 98% of the theoretical density and showed a similar grain size dependence.