摘要
利用非均相沉淀包裹技术,在室温于水溶液中,以球形αAl2O3、硫酸镍、硫酸亚铁和碳酸氢铵为原料,先制备了无定形碱式碳酸镍和水合氧化铁包裹氧化铝球形微粉前驱体。然后,前驱体在600℃经氢气还原2 h制备表面光滑、致密的γFeNi包裹Al2O3复合微球。利用扫描电镜、能量散射分光仪、X射线衍射和热重分析仪等表征了复合微球前驱体及还原产物的表面和断面形貌、成分以及前驱体热分解过程。对被包裹氧化铝含量、加料速度、搅拌速度、反应时间及表面活性剂等影响因素进行了分析。初步得到优化制备条件,即15 g/LαAl2O3,加料速度为5 mL/min,搅拌速度为1 000 r/min,反应时间为1 h,表面活性剂添加量为5 mL/L。γFeNi的热膨胀系数接近于氧化铝,因而使两者形成了较好的界面结合。这种γFeNi包裹Al2O3复合微球可用作新型吸波材料。
The precursor of fine powder alumina microspheres wrapped by both amorphous basic nickel carbonate and hydrated ferric oxide was synthesized at room temperature in watery solution by the heterogeneous precipitation wrapping technique using α- Al2O3 powders, nickel sulfate, iron（Ⅱ） sulfate and ammonium bicarbonate as raw materials. Then, the surface smoothly and densified γ- FeNi-coated alumina composite microspheres were successfully prepared by reducing the precursor in an H2 atmosphere at 600℃ for 2 h. The morphology, phase components and process of thermal-decomposition process of the precursor and the subsequently reduced microspheres were characterized by scanning electron microscope, energy dispersive spectroscope, X-ray diffraction and thermogravimetric analysis. The effects of the content of α-Al2O3 microspheres, rates of adding nickel sulfate, iron sulfate and ammonium bicarbonate solutions, mechanical stirring speed, reaction time and the content of surface active reagent were studied respectively to determine the optimal preparation conditions. The optimum conditions are an α- Al2O3 of 15 g/L, rate of for 5 mL/min adding raw materials, a stirring speed of 1 000 r/min, 1 h of reaction time, and surfactant content 5 mL/L. A well-coherent interfacial structure between the metal shell and Al2O3 core for the γ-FeNcoated alumina composite microspheres was formed owing to the relatively matched thermal expansion coefficient between γ-FeNi alloy and α-Al2O3. The materials consisting of γ-FeNi-coated alumina composite microspheres can be used in newly developed wave absorbing materials.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2005年第9期1163-1168,共6页
Journal of The Chinese Ceramic Society
基金
江苏大学自然科学创新预研基金(04CX01)资助项目
关键词
非均相沉淀
γ-铁镍合金包裹氧化铝
复合微球
heterogeneous precipitation
iron nickel alloy-coated alumina
composite microspheres
