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研究了微米级Al粉高温诱导Na2O-CaO-Si O2玻璃生成板状α-Al2O3晶体的形成过程并分别用X射线衍射仪及环境扫描电镜观察了生成晶体的形貌,用DSC/TG对混合粉体进行了热分析.X射线衍射分析及环境扫描电镜测试表明,1 200 ℃下,晶体直径为400 ～1 000nm,大部分呈聚集状态,部分晶体交互生长,且大部分的晶体发育于玻璃的界面,晶体与基体可以形成良好的润湿.DSC/TG表明,较低温下Al氧化后生成的γ-Al2O3转变为α-Al2O3,形成的α-Al2O3由于熔融的Al及玻璃提供的液相环境充分形核并生长,部分熔融的Al热侵蚀玻璃,导致玻璃的局部组成偏离Na2O-CaO-Si O2系统的三元组成,形成局部Na2O-Al2O3-Si O系统,并为形成NaAlSi O提供了必要条件.
The formation process of NaAl2O-CaO-Si O2 glass into α -Al2O3 crystal was studied at high temperature induced by micron Al powder. The morphology of the crystal was observed by X-ray diffraction and environmental scanning electron microscope. The results of X-ray diffraction (XRD) and scanning electron microscopy (SEM) show that the crystal diameter of 400-1000 nm at 1 200 ℃, most of them are aggregated, and some crystals grow alternately, and most of the crystals develop in the glass , The crystal and the matrix can form a good wetting.DSC / TG shows that the γ-Al2O3 generated after the Al oxidation at lower temperature is transformed into α-Al2O3, and the α-Al2O3 formed due to the melted Al and the liquid phase provided by the glass The environment is fully nucleated and grown, partially melted Al hot-erodes the glass, causing the local composition of the glass to deviate from the ternary composition of the Na2O-CaO-Si O2 system, forming a localized Na2O-Al2O3-SiO system and providing a Necessary conditions.