基于气-液-固机理的单晶蓝宝石纤维的制备与表征

Preparation and characterization of single crystal α-Al2O3 fiber based on VLS mechanism

单晶蓝宝石(α-Al2O3)纤维作为强韧化关键基础材料,在陶瓷、金属、高分子基等复合材料领域具有广泛的应用前景。以SiO2粉体和金属铝棒为原料、氩气为保护气、氧化锆(ZrO2)陶瓷为承烧板,利用气相-液相-固相(VLS)沉积反应机理制备单晶α-Al2O3纤维。通过X射线衍射、扫描电子显微镜、场发射透射电子显微镜、能量色散谱仪等表征技术分别对单晶α-Al2O3纤维纯化前后的相结构、微观形貌和组成进行表征。结果表明:单晶α-Al2O3纤维表面光滑,粗细均匀;纤维平均直径为0.5~1μm;纯化前后的单晶α-Al2O3纤维均为单晶α相,主要由(104)、(110)和(006)晶面组成,纯化后纤维中无杂质相。在此基础上,进一步探讨了单晶α-Al2O3纤维的生长机理和生长过程,为单晶α-Al2O3纤维大规模可控制备及应用奠定实验基础。

As a key fundamental strengthening-softening material,single crystal sapphire fiber can be widely used in ceramic,metal,and polymer based composite materials.Using vapor-liquid-solid(VLS)deposition reaction mechanism,single crystal sapphire fiber was prepared with SiO2 powders and aluminum bar as raw materials,argon as protective atmosphere and ZrO2 ceramics as setter plate.SEM,XRD,HRTEM and EDS were performed to analyze the morphology,structure and element.The results indicated that the fiber was smooth and true and the average diameter was about 0.5~1μm.The Al2O3 fiber was single crystalα-phase before and after purification and there was no impurity present in the fiber after purification.The main lattice planes were comprised of(104),(110)and(006).Next,VLS growth mechanism and process of single crystal sapphire fiber was studied.The results layed an experimental foundation for the extensive and controllable preparation and application of single crystal sapphire fiber.