勃姆石
微观结构
播种
成核
材料科学
化学工程
转化(遗传学)
动力学
透射电子显微镜
溶胶凝胶
扫描电子显微镜
活化能
矿物学
化学
冶金
复合材料
纳米技术
铝
热力学
物理化学
有机化学
生物化学
物理
量子力学
基因
工程类
作者
R. A. Shelleman,Gary L. Messing,Miho Kumagai
标识
DOI:10.1016/0022-3093(86)90142-0
摘要
The kinetics and surface area changes during the γ to α-Al2O3 transformation sequence of an α-Al2O3 seeded boehmite sol-gel are compared to an unseeded boehmite sol gel. The seeded gels exhibited increased kinetics, however the activation energy for the γ to α-Al3O3 transformation was lowered only 17% indicating the α-Al2O3 transformation is growth controlled. Transmission electron microscopy showed that each α-Al2O3 seed acts as a multiple nucleation site for the θ to α-Al2O3 transformation. The higher surface area of the seeded boehmite results from the prevention of vermicular microstructure development. Thus, by seeding boehmite sol gels with α-Al2O3 the growth process during transformation to α-Al2O3 is controlled resulting in a fine, uniform microstructure which sinters at significantly lower temperatures.
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