溶胶-凝胶论文：氧化铝纳米结构纤维的制备及性质.doc

溶胶-凝胶论文：氧化铝纳米结构纤维的制备及性质【中文摘要】本论文采用溶胶凝胶方法结合静电纺丝技术制备了氧化铝凝胶纤维,然后经过高温煅烧得到了片层状的-Al2O3纳米结构陶瓷纤维,研究了其制备过程及耐热性,并成功测定了单根纤维的力学性质。同时还制备了不同SiO2含量的氧化铝纳米结构陶瓷纤维,研究了氧化硅对氧化铝陶瓷纤维的形貌、物相结构、导热系数等方面的影响,探讨了氧化铝纳米结构陶瓷纤维的形成机理,丰富和发展了氧化铝纳米结构陶瓷纤维的制备方法。1.柔性-Al2O3纳米结构纤维的制备与表征通过溶胶凝胶方法结合静电纺丝技术制备了氧化铝凝胶纤维,经过高温煅烧得到了柔性-Al2O3纳米结构纤维。具体的制备方法是将氯化铝和异丙醇铝溶解在水和乙醇中,用冰醋酸和盐酸为催化剂,使异丙醇铝水解为小胶粒,用PVP为纺丝助剂,控制纺丝条件,制备了棉花状的氧化铝凝胶纤维。将制得的凝胶纤维通过两段煅烧,制备了由-Al2O3纳米片构成的柔性纳米结构纤维。通过XRD、SEM、IR、TG等分析手段对-Al2O3纳米结构纤维进行了详尽的表征。结果表明：-Al2O3纳米结构纤维由3050 nm厚的纳米片构成,纤维表面致密,没有孔洞和裂纹,经1400/2h耐温测试,纤维结构没有发生明显的改变,纳米片没有明显长大。力学性质测定表明,直径为10.4m的单根纤维,断裂强度为142.5MPa,断裂伸长率为1.49%,而直径为7.5m的单根纤维断裂强度和断裂伸长率分别为407.7 MPa和2.5%。表明随纤维直径的缩小,断裂强度和断裂伸长率增大。2.掺杂SiO2的氧化铝纳米结构纤维的制备及表征以氯化铝和异丙醇铝为铝源,正硅酸乙酯为添加剂,水和乙醇为共溶剂,冰醋酸和盐酸为混合催化剂,PVP为纺丝助剂,经静电纺丝制备了掺杂1%4%Si02的氧化铝纳米结构纤维。通过XRD、SEM、IR、TG等分析手段对氧化铝纤维进行了详细的表征。所制备的不同SiO2含量的氧化铝纤维由纳米片和纳米颗粒组成,随着SiO2含量的增加,氧化铝纤维的物相结构和形貌发生了明显的改变,氧化铝晶相的转变温度也随SiO2含量的不同而改变。掺杂1%-4%SiO2的氧化铝纤维经1400煅烧后,得到直径约为300850 nm的氧化铝纳米结构纤维,纤维表面致密,没有明显的孔洞和裂纹。因纤维直径小、致密,表现出很好的柔韧性。经测试,-Al2O3纤维有最小的导热系数0.0476 W/m-K,经1400/2h煅烧后,-A12O3转化为a-Al2O3,纤维的导热系数增大为0.0773 W/mK。【英文摘要】In this paper, alumina gel-fibers were synthesized through combining sol-gel and electrospinning process, and then calcined at high temperatures, so the lamellae-Al2O3 fibers with nanostructures were fabricated. Its preparation and heat resistance were studied. The microstructure of fibers and mechanical properties such as fracture strength and elongation were characterized. And alumina with nanostructured ceramic fibers with different SiO2 content were prepared, the morphology, crystal phase and the thermal properties of alumina ceramic fibers were influenced by SiO2 content. The formation mechanism of alumina fibers was discussed. The theory and methods of the preparation of alumina fibers were enriched and developed.1. Fabrication and characterization of flexible nanostructured-Al2O3 fibersThe dense flexible-Al2O3 fibers with nanostructures were fabricated by sol-gel-electrospinning process. The microstructure of fibers and mechanical properties such as fracture strength and elongation were characterized. Moreover, the factors affecting the fiber properties were discussed. The-Al2O3 fibers were composed with 3050 nm nanoflakes, and no small holes or cracks were observed in those, which exhibited superior good thermal shock resistance and higher fracture strength and elongation compared with the commercial-Al2O3 fiber. First, AICl36H2O and AIP were dissolved in water and ethanol, and then HAc and HCl were added as catalyzes to accelerate AIP hydrolyze to small grains. With PVP as spinning aids, gel fibers were fabricated by electrospinning. After two stage calcinations,-Al2O3 fibers with nanostructures were fabricated. The fibers were characterized in detail by XRD, SEM, IR, TG and other techniques.2. Preparation and characterization of nanostructured alumina fibers with different SiO2 content Nanostructured alumina fibers with different SiO2 content were fabricated through electrospinning technique using AICl36H2O and AIP as reagent, TEOS as doping reagent, HAc and HC1 as catalyzers and PVP as spinnable aids. The fibers were characterized by XRD, SEM, IR and TG. The products were composed with nanoflakes and nanoparticles. It was found that the amounts of SiO2 had significant effects on the morphology and crystalline phase of the alumina fibers. The crystalline phase transition temperature of alumina fibers was also different with the change in the amount of SiO2. The as-prepared alumina fibers were longer than several thousands micrometers with uniform diameter of 300-850 nm after 1400calcination. The alumina fibers were dense, and no small holes or cracks were observed in those, which exhibited superior good flexible. The thermal conductivity of-Al2O3 fibers was the smallest, which was 0.0476 W/m-k. The crystalline phase of-Al2O3 fibers was transited to-Al2O3 fibers after 1400calcination, the thermal conductivity was increased to 0.0773 W/m-k.【关键词】溶胶-凝胶 静电纺丝 -Al2O3 纳米结构纤维【英文关键词】sol-gel electrospinning -Al2O3 nanostructured fiber【目录】氧化铝纳米结构纤维的制备及性质摘要6-8ABSTRACT8-9第一章 绪论10-261.1 溶胶凝胶-电纺技术发展概述10-161.1.1 溶胶凝胶及电纺技术的基本原理11-141.1.2 溶胶凝胶结合电纺技术制备陶瓷纳米纤维的现状与研究进展14-161.2 氧化铝纤维的研究背景16-191.3 氧化铝纤维的性质及应用19-201.4 本课题选择的目的及意义20-211.5 参考文献21-26第二章 柔性-Al_2O_3纳米结构纤维的制备与表征26-382.1 前言26-272.2 实验部分27-282.2.1 原料与试剂272.2.2 -Al_2O_3纳米结构纤维的制备272.2.3 表征27-282.3 结果与讨论28-352.3.1 凝胶纤维的制备29-302.3.2 凝胶纤维的陶瓷化过程30-322.3.3 -Al_2O_3纤维的微观结构及耐热性32-342.3.4 -Al_2O_3纤维的力学性质34-352.4 结论352.5 参考文献35-38第三章 掺杂SiO_2的氧化铝纳米结构纤维的制备及表征38-553.1 前言38-393.2 实验部分39-403.2.1 原料与试剂39-403.