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采用热蒸发法制备出高纯度线状、棒状、多脚状的不同形态ZnO晶须材料.研究了氮气流量、反应温度、反应时间(保温时间)等因素对产物规整率、转化率及长径比的影响.利用SEM对产物形态进行表征.结果表明:采用不同条件的热蒸发法可制备出高质量不同形态的ZnO晶须.反应过程中锌蒸压气对产物形态的影响较大.以陈化锌粉为原料,在1000~1100℃保温较短的时间,并始终以0.2m3/h通入高纯氮气,得到棒状晶须;保温时间较长,得到线状晶须.而多脚状ZnO晶须则是在通入高纯氮气时间较短的情况下得到的. 相似文献
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利用碳热还原法,将锌粉和碳粉混合后在马弗炉中有梯度地加热,制得了针状ZnO晶须。利用XRD和SEM分别对ZnO晶须的结构和物相、形貌和尺寸进行分析,还分析了制得的ZnO晶须的吸波性能。结果表明,制得的ZnO晶须纯度高,结晶度高;ZnO晶须排列致密,呈针状结构,直径为20~50μm,长度超过700μm,长径比>14,符合晶须标准;m(Fe)∶m(ZnO)=4∶1与1∶1复合粉体的电磁损耗相近,但改变ZnO的含量在一些频率段电磁损耗程度不同,说明ZnO晶须加入量的改变对复合粉体的吸波性能有一定的影响。 相似文献
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首先以乙醇为溶剂,乙酸锌为前驱体,油酸钠为表面修饰剂,采用溶液化学法,制得ZnO纳米粒子。以自制ZnO纳米粒子为基体,通过煅烧方法制备针状ZnO纳米线束。通过紫外-可见吸收光谱(UVVis)、荧光光谱(FL)、透射电子显微镜(TEM)、X射线衍射(XRD)和扫描电子显微镜(SEM)等方法对合成的样品进行表征。结果表明,所合成ZnO纳米粒子样品UV-Vis吸收光谱在355nm给出ZnO纳米粒子的特征吸收峰,FL光谱显示在400和550nm处产生荧光发射。ZnO纳米粒子尺寸约为5nm且粒径分布较窄。自制ZnO纳米粒子样品经500℃煅烧后可得到针状ZnO纳米线束。纳米线为六方晶系纤锌矿结构ZnO单晶纳米线,长度约为10μm,直径约为100nm,长径比约为100,且具有良好的紫外发光性能。 相似文献
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乙醇/水混合溶剂沉淀制备纳米SrF_2及其粒径控制 总被引:1,自引:0,他引:1
本文采用水/乙醇混合溶剂沉淀法,制备了不同粒径的SrF2纳米粉体,也在不同pH值的水溶液和不同表面活性剂CTAB、SDS的水溶液中,研究制备了纳米SrF2。用XRD、TEM观测分析了粉体的粒径和形貌。在纯水和水/乙醇体积比3∶1,1∶1,3∶5,1∶4的混合溶剂中,获得SrF2沉淀的粒径分别为32nm,19nm,23nm,16nm和13nm,粒径总体上随混合溶剂中乙醇含量升高而减小,其分散性和形貌规则性也随乙醇含量升高而变好。水溶液的pH值和表面活性剂对SrF2沉淀粒径无明显影响,相比之下,混合溶剂对粒径的影响显著。 相似文献
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通过溶剂热法(无水乙醇)制备了Cu2+(0~6mol%)掺杂ZnO纳米棒粉体,采用X射线衍射仪和扫描电镜对掺杂ZnO纳米粉体的晶体结构和微观形貌进行了表征.研究了Cu2+掺杂比例、溶剂热反应温度及时间对材料气敏性能的影响;考察ZnO(120℃,10h)和3mol%Cu2+掺杂ZnO(120℃,10h)粉体对应元件对甲醛、乙酸、甲苯、乙醇、丙酮、三甲胺等六种气体的气敏性能.结果表明:通过溶剂热法制备的ZnO粉体为纳米棒状结构,棒长度和直径随Cu2+掺杂比例不同发生变化;3mol%Cu2+掺杂ZnO(120℃,10h)样品对应元件对低浓度乙醇有很好的选择性,在395℃工作温度下对1×10–3乙醇的灵敏度为380.5,响应和脱附时间分别为5 s和40 s,对1×10–6乙醇的灵敏度可达4.2. 相似文献
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ZnO晶须增强树脂基复合材料研究 总被引:14,自引:0,他引:14
对ZnO晶须/NR复合材料的实验研究表明,表面改性后的ZnO晶须对NR具有显著的增强和抗老化作用,其增强效果沿橡胶混炼剪切方向与垂直剪切方向几乎相同。对ZnO晶须/PPS复合体系的研究结果表明,偶联剂表面处理后的ZnO晶须对PPS有显著的增强作用。研究发现,经典的预测复合材料强度的理论公式可以较好地预测ZnO晶须/NR体系,但对ZnO晶须/PPS复合材料的预测则与实测值存在较大差异。分析认为其主要原因是该晶须特殊的空间四针状结构能有效地传递受力.尖端作用避免了端口应力集中引起的破坏。 相似文献
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离子交换树脂法制备氧化锌晶须 总被引:4,自引:0,他引:4
以离子交换树脂为沉淀剂,通过锌盐化学沉淀法合成了前驱体Zn(OH)2,进一步灼烧制备氧化锌晶须.利用扫描电镜(SEM)对其进行了形貌分析.初步探讨了合成Zn(OH)2的实验条件,研究了不同烧结温度对ZnO晶须的影响. 相似文献
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ZnO whiskers were prepared by a solvothermal process with Zn(OH)4(2-), cetyltrimethylammonium bromide (CTAB), n-amyl alcohol and n-hexane at 140 degrees C. The influence of preparation condition on the morphology of the resultant sample was investigated through change zinc salts, co-surfactants, surfactants, reaction temperature, and reaction time. Experimental results revealed that the morphology of as-obtained ZnO was affected strongly by the zinc salts and surfactants. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron diffraction (ED). Results showed that ZnO whiskers had the diameters of 100-500 nm, the lengths of several microm, and grown along orientation of [0001]. The gas sensitivities of the as-prepared ZnO whiskers were detected. The results revealed that the ZnO whiskers had excellent potential application for gas sensor. 相似文献
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In this work, ZnO whiskers with different sizes and hexagonal ZnO platelets were successfully prepared by a simple solution route at low temperature (85 °C), using zinc chloride and sodium hydroxide as the reactants. The influence on the morphology of the products was investigated while the type of the alcohol solvent changed. It is believed that interface–solvent interaction is responsible for the evolution of ZnO crystals. Resultant products have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM) and selected area electron diffraction (SAED). 相似文献
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以锌粉为原料,采用碳还原剂控制法制备了四脚状氧化锌晶须。用光学显微镜、扫描电子显微镜及X射线衍射分析方法对产物进行了表征。实验结果表明,该晶须为纯氧化锌,属于六方晶系纤锌矿结构;整个氧化锌晶须基本为四脚状晶须结构。通过热力学分析及试验表明,在1220~1350 K的温度时,可以得到完整的四脚状氧化锌晶体。用波导法对所得晶须进行了磁导率和介电常数的测量。微波电磁性能试验表明,四脚状氧化锌晶须是一种介电损耗材料,具有一定的微波吸收性能。 相似文献
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提出一种自石灰石矿粉中直接提取CaCO_3晶须的碳化-分解方法。该方法能够以天然石灰石矿粉为原料,通过水溶性碳酸的作用溶解出Ca(HCO_3)_2,进而在升温条件下通过Ca(HCO_3)_2的分解反应得到形貌规整的棱锥状CaCO_3晶须。扫描电镜观测与X射线衍射分析显示,Ca(HCO_3)_2分解温度对CaCO_3晶须微观形貌的影响显著,晶须长度与长径比随分解温度的升高均呈上升趋势,但分解温度超过80℃会导致文石晶相向方解石晶相转化。实验结果表明,80℃、2h条件下,Ca(HCO_3)_2分解产物中文石晶相含量较高,晶须几何形貌更为合理,其平均长度为14.61 μm、长径比为8.10。 相似文献
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Guihua Peng Guojian Jiang Hanrui Zhuang Wenlan Li Suying Xu 《Materials Research Bulletin》2005,40(12):2139-2143
β-Si3N4 whiskers with diameter of 0.5–2 μm and aspect ratio of 10–15 have been successfully prepared by combustion synthesis under 30–50 atm nitrogen pressure. The addition of MgSiN2 powder plays a significant role in the growth of β-Si3N4 whiskers. The as-prepared products were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). 相似文献
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ZnO nanorods of 25 nm with quite homogeneous size and shape have been fabricated by introducing ZnO sols as nucleation centers prior to the hydrothermal reaction. The samples were characterized by scanning electron microscope, transmission electron microscope, X-ray diffraction, photoluminescence and resonant Raman spectra. After ZnO sols are introduced, the width of the resulting nanorods decreases above an order of magnitude and the aspect ratio increases 5 times. The increase of the intensity ratio of ultraviolet to visible emissions in room-temperature photoluminescence spectrum and the decrease of the Raman linewidths show the improvement in the quality of ZnO nanorods. Influences of the number of seed nuclei and the aging time of ZnO sols on the morphology of ZnO nanorods are discussed. 相似文献
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高长径比硼酸镁晶须的制备及生长机理研究 总被引:4,自引:0,他引:4
以六水氯化镁和硼砂为原料, 以氯化钠、氯化钾作为助熔剂, 通过熔盐法制备出长为200~800μm, 最大长径比为250, 品质均匀的硼酸镁晶须. 采用XRD分析、光学显微和SEM观察, 研究产物的结构和形貌, 并研究不同n(B)/n(Mg)、反应温度和时间对硼酸镁晶须生长过程及质量的影响, 结果表明, 反应的最佳条件是n(B)/n(Mg)=3:1、反应温度为900℃、恒温时间为6h. 根据XRD分析, 表明Mg2B2O5晶须的生成经过中间产物方硼石Mg3B7O13Cl的转化过程, 晶须生长需要一个富硼的环境. 晶须的生长机理符合L-S机理. 相似文献
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Hu X Masuda Y Ohji T Saito N Kato K 《Journal of nanoscience and nanotechnology》2011,11(12):10935-10939
Bunch-shaped ZnO nanowires film was successfully fabricated by the forced-hydrolysis-initiated-nucleation of anhydrous zinc acetate in an aqueous solution of zinc acetate and sodium hydroxide at low temperature. X-ray diffraction and a field emission scanning electron microscope clarified their formation mechanism and morphology development. The morphology was controllable by adjusting the solution temperature and deposition time. ZnO nanowires obtained at 65 degrees C for 6 h have a high aspect ratio of about 106. The smaller diameter with higher aspect ratio of ZnO nanowires, the easier the formation of bunch shapes by the capillary force during the drying process. This fabrication technique indicated that bunched ZnO film was prepared at low cost, and fittable to low heat-resistance substrates such as a polymer substarte. 相似文献
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Flash synthesis of flower-like ZnO nanostructures by microwave-induced combustion process 总被引:1,自引:0,他引:1
Flower-like ZnO particles were fabricated from zinc nitrate and urea via the microwave-induced combustion technique (MICT). The structure and morphology of the products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). The effects of growth conditions such as microwave power, radiation time, and molar ratio of urea/Zn2+ were investigated. Results show that the morphologies and particle sizes of the final products depend on the molar ratio of urea/Zn2+. The SEM images of ZnO flowers grown in different periods were employed to explain the formation mechanism. This study provides a simple and efficient approach for synthesizing flower-like ZnO heterostructures. 相似文献