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射频等离子法制备的TiO2纳米晶、PAN预氧化纤维纳米尺度微观结构研究

Study on Microstructures at Nano Scale of TiO2 Nanocrystalline, PAN Preoxidized Fibers Prepared with Radio Frequency Plasma

【作者】 徐海萍

【导师】 孙彦平;

【作者基本信息】 太原理工大学 , 化学工程与技术, 2005, 博士

【摘要】 纳米材料及材料的纳米尺度微观结构研究是材料科学的两个重要领域。纳米材料的结构与制备条件密切相关,表征是准确判断制备条件对其结构影响的唯一途径。材料的微观结构表征应采用多种手段,从多角度、多尺度下进行,表征手段应准确、方便、有效,且各种手段对同一结构特征的表征结果应一致,才能指导实验并为新的制备技术提供依据。 等离子体系统,可在“快速、纯净、高活性”条件下使反应发生。等离子体在材料制备中的作用,一是可用于纳米材料的制备;二是可提高所制备材料微晶结构的有序化。 射频等离子体的最大特点是采用无极放电,不存在电极损耗污染。射频高温等离子体,由于其高效、清洁等特点尤其适于制备纳米催化材料或半导体材料,如作为光催化剂的TiO2纳米晶。而利用射频低温等离子体的高能量,可使制备碳纤维、石墨化纤维所用原丝,如PAN(聚丙烯腈),在预氧化阶段的较低温度下,其微观结构向有序化方向转变。纳米TiO2及PAN预氧化纤维是高、低温射频等离子制备技术应用中具有代表性的两类材料,其制备过程、表征手段等对等离子法制备的其它纳米材料,或在纳米尺度下研究材料微观结构的工作具有一定的借鉴作用和参考价值。 TiO2纳米晶的粒径、尺寸分布、晶型及晶相组成等对光催化活性影响很大,由于其它方法制备的TiO2结晶度较差且易引起颗粒硬团聚等原因,

【Abstract】 Nano materials and microstructures of materials at nano scales are two key regions on the study of material science. The structures of nano materials are closely related to the preparation conditions, and characterization is the unique way to accurately judge how the preparation conditions affect the structures. The microstructures of materials should be characterized using varied means, in different angles and multiple scales. The characterization meanes should also be accurate, convenient and effective. At the mean time, only the identical characterization results for the same structure feature using different means that can guide experiments and provide scientific basis for the new preparation techniques.Plasma system can make the reactions happen under conditions of fastness, purity and high activity. The roles of plasma playing on material preparation are: one is for the preparing of nano materials, the other one is for the increasing microcrystalline structure ordering of the prepared materials.The maximum characteristic of radio frequency plasma is that there is no electric pole in the discharge space, so it is in nonexistence of dissipation

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