【作者】 刘晶冰；

【导师】 严辉； 汪浩；

【作者基本信息】 北京工业大学 ， 材料物理与化学， 2005， 博士

【摘要】 与金属、塑料相比,陶瓷材料具有优异的耐高温和抗腐蚀等良好的性能,因此广泛地应用于尖端科技领域。伴随纳米科学技术的发展,产生了纳米陶瓷,它的问世将使材料的强度、韧性和超塑性大大提高。纳米陶瓷的研究是当前先进陶瓷发展的三大课题之一。而陶瓷是由原料成型后烧结而成的,陶瓷粉体的质量决定了陶瓷材料的微观结构和宏观性能。因此,发展先进陶瓷的首要问题是要有符合要求的原料——粉体。用于合成陶瓷粉体的方法有多种,如:固相合成法、沉淀法、溶胶凝胶法、水热法等。其中,水热法合成的陶瓷粉体具有晶粒结晶良好,形貌可控,纯度高及晶粒尺寸分布窄等特点,近年来已被广泛地应用于各种陶瓷粉体的制备。而微波合成技术能够在短时间内合成纯度高、粒度细的陶瓷粉末,已引起广泛重视。本文旨在探索纳米功能陶瓷粉体的低温水热与微波辅助合成新方法、新路线,优化其合成条件,研究陶瓷粉体在水热与微波辅助条件下的形成及形貌控制机理,同时探讨了粉体质量对陶瓷显微结构和性能的影响,取得了一些工作进展归纳起来可概括为以下六个部分: 1. 设计了可行的水热合成新路线,利用水热法在100~140oC 成功地合成出结晶性良好的纯相HAP 纳米微粒;研究了水热合成过程中溶液pH 值、反应温度等实验参数对所得HAP 结构和形貌的影响。结果表明:溶液pH 值对所得HAP 的形貌有重要影响;低的pH 值有利于羟基磷灰石的针状生长;通过控制上述参数可以获得长径比为8-20,平均直径和长度分别为40nm和600nm 的HAP 纳米晶须。2. 采用微波辅助合成技术在10min 内合成出纯度高的羟基磷灰石陶瓷粉末。考察了微波反应过程中溶液pH 值、络合剂等实验参数对产物结构、形貌及尺寸的影响。在以EDTA 作为络合剂的情况下,通过调节溶液的pH 值可以获得棒状、蝴蝶结状及花状的纳米结构,这是首次尝试用微波法合成三维HAP 纳米结构。3. 简单介绍了传统的成核与晶体生长理论,阐述了纳米微粒(晶粒)生长的特殊性及现有晶体生长理论在这类体系中应用的局限性,进而引入负离子更多还原

【Abstract】 Compared with metal and plastic, ceramic materials have many advantages such as heat resistant and anti-rusty, which have been extensively applied to advanced technological fields. With the development of nanotechnology, nanoceramics come into being, which improve the strength and toughness of the materials. Studying on the nanoceramics becomes one of the most important tasks in the development of advanced ceramic. Ceramic powder is a necessary ingredient for the ceramics. The performance characteristics of a ceramic component are greatly influenced by precursor powder characteristics. The most crucial factor for the development of advanced ceramic is to prepare the satisfying ceramic powders. Many methods are applied for preparing the ceramic powders, such as solid state reaction, precipitation, sol-gel and hydrothermal method and so on. The hydrothermally prepared powders offer many advantages, such as high degree of crystallinity, well-controlled morphology, high purity and narrow particle size distribution. This method has been widely used in preparation of various powders in recent years. Compared with conventional method, microwave synthesis has the advantages of very short time, small particle size, narrow particle size distribution, and high purity, which make it become an active domain of scientific researches. The present thesis is aimed at exploring novel low-temperature hydrothermal & microwave irradiation methods to synthesize nanoscale functional ceramic powders, and studying the formation and morphology controlled mechanism of the ceramic powders under the hydrothermal & microwave conditions. The main researches achieved are summed up as following: 1. We succeeded in the synthesis of well crystallined phase-pure HAP nanoparticles by a simple hydrothermal method at 100~140oC. The effects of the pH value and the reaction temperature on the formed phase and morphology of HAP during the hydrothermal process were also investigated. The results indicated that they are all influencing factors on the phase and morphology of the final products. Lower pH value is favorable for the formation of needle like HAP. On controlling the above factors, well crystallined and uniform HAP nanowiskers were obtained. 2. We adopted microwave irradiation method to synthesize pure phase HAP powders in 10min. During the microwave treatment process, the effects of the pH value and complex reagent on the properties of the obtained product such as更多还原