不同形貌微纳米材料的制备及其电磁性能研究

发布时间：2018-02-21 11:14

本文关键词： 空心Co_3O_4 竹节状β-SiC 磁性光致发光吸波性能　出处：《西北工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：微纳米材料结构独特、物理化学性能优异且应用前景广阔,已成为科研工作者们研究的热点。迄今为止,已研究开发出若干微纳米材料成熟的合成工艺,并制备出具有特殊物理化学性能的微纳米材料。在这些材料中,除成分外,形貌仍属影响其性能的主要因素。本文研究工作主要集中在两个方面:第一,通过水热合成法,并立足于工艺简单、绿色环保的基础上制备出空心球形的四氧化三钴(Co3O4),并探索研究其静态磁性和光致发光性能;第二,采用熔盐法合成出β型碳化硅(β-SiC)纳米晶须,并系统、深入地研究其吸波性能。具体研究内容如下:(1)以葡萄糖(C6H12O6)为碳源、六水硝酸钴(Co(NO3)2?6H2O)为钴源,采用水热法一步合成出球形钴氧化物(C@Co3O4),后经550oC空气中焙烧去除碳核,获得了形貌一致的Co3O4空心球;以氯化钠-氟化钠(NaCl-Na F)二元混合盐为中间媒介、硅粉(Si)及多壁碳纳米管(MWCNT)分别为硅源和碳源,采用熔盐法(1250oC保持6 h),获得了竹节状的β-SiC纳米晶须。(2)利用XRD、SEM、TEM、XPS和拉曼谱等表征手段,系统分析了合成产物的微观形貌和晶体结构。结果表明:空心结构的Co3O4是由大量无数微小粒子组成,且其产物覆盖率高达75%;而直径介于150~250 nm范围的β-SiC纳米晶须则呈竹节状,且每一竹节包含大量的缺陷,如孪晶、层错等。(3)分别利用超导量子干涉仪和F-320型荧光光谱仪对Co3O4在室温下的静态磁性和光致发光性进行研究。结果发现,Co3O4空心微纳米球具有弱铁磁性和良好的光致发光行为。(4)采用同轴传输线法并利用美国惠普8720B型矢量网络分析仪测试β-SiC与石蜡复合样品在2-14 GHz范围内的电磁参数。根据所测电磁参数,计算样品在2-14 GHz范围内的介电损耗因子(tanδε)和反射损耗值(RL)。结果表明:β-SiC纳米晶须的电磁参数变化较明显,其tanδε平均值约为0.6,这高于其他文献的相应报道。特别地,当β-SiC质量分数为30%、匹配厚度为1.9 mm时,β-SiC纳米晶须的RL值最小(-48.13 dB)。可见,β-SiC纳米晶须有望成为质量轻、厚度薄的吸波材料。
[Abstract]:Because of its unique structure, excellent physical and chemical properties and wide application prospects, micronanomaterials have become a hot research topic of researchers. Up to now, some mature synthetic processes of micro- and nano-materials have been developed. In addition to the composition, the morphology is still the main factor affecting the properties of these materials. The research work in this paper mainly focuses on two aspects: first, by hydrothermal synthesis, Based on the simple process and green environment, hollow spherical Co _ 3O _ 4O _ 4O _ 4 hollow spheres were prepared, and their static magnetic and photoluminescence properties were investigated. Secondly, 尾 -type silicon carbide (尾 -SiC) nano-whiskers were synthesized by molten salt method, and the system was developed. The specific contents of the study are as follows: 1) using glucose C6H12O6) as carbon source, cobalt nitrate hexahydrate (CoCoHNO _ 3) _ 2? 6H 2O) as cobalt source, the spherical cobalt oxide CCO3O4N was synthesized by hydrothermal method, and then roasted in 550 OC air to remove the carbon nucleus, and the Co3O4 hollow spheres with the same morphology were obtained, and the mixed salt of sodium chloride and sodium fluoride was used as the intermediate. SiSi) and MWCNT (multiwalled carbon nanotubes) are silicon and carbon sources respectively. The 尾 -SiC nanocrystalline whiskers with bamboo-like shape have been obtained by means of molten salt method (1250oC) for 6 h, and characterized by XRDX SEMTEMU XPS and Raman spectroscopy. The micromorphology and crystal structure of the synthesized products are systematically analyzed. The results show that the hollow Co3O4 is composed of a large number of tiny particles, and the product coverage is as high as 75cm, while the 尾 -SiC nanowhiskers with diameter between 150nm and 250nm are bamboo-shaped. And each piece of bamboo contains a large number of defects, such as twins, The static magnetism and photoluminescence of Co3O4 at room temperature were studied by superconducting quantum interferometer and F-320 fluorescence spectrometer respectively. The results show that the hollow Co3O4 microspheres have weak ferromagnetism and good photoluminescence. Behavior # 4) the electromagnetic parameters of 尾 -SiC and paraffin complex samples in the range of 2-14 GHz were measured by coaxial transmission line method and Hewlett-Packard 8720B vector network analyzer. The results show that the electromagnetic parameters of 尾 -SiC nanocrystalline whiskers vary more obviously, and the average tan 未蔚 is about 0.6, which is higher than that reported in other literatures, especially, the dielectric loss factor of 尾 -SiC nanocrystalline whiskers is calculated in the range of 2-14 GHz, and the results show that the average tan 未蔚 of 尾 -SiC nanocrystalline whiskers is about 0.6, which is higher than that reported in other literatures. When the mass fraction of 尾 -SiC is 30 and the matching thickness is 1.9 mm, the RL value of 尾 -SiC nano-whisker is the smallest (48.13 dB). It is shown that 尾 -SiC nano-whisker is expected to become a light and thin wave absorbing material.
【学位授予单位】：西北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1

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