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一维ZnO晶须的制备与生长机理 总被引:4,自引:0,他引:4
以Zn粉为原料,采用气固反应方法制备出两种一维ZnO晶须:ZnO纳米线和ZnO短晶须。用XRD、SEM等分析手段对ZnO晶须的结构和形貌进行研究,并分析了两种ZnO晶须的生长机理。 相似文献
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采用自制的圆锥式混炼器对环氧树脂(EP)/ZnO晶须复合材料进行共混。研究了ZnO晶须含量、混炼器混合和机械混合两种方式以及混炼器混炼间隙对EP/ZnO晶须复合材料力学性能和导热系数的影响。研究发现,无论采用何种混合方式,随着ZnO晶须含量的增加,EP/ZnO晶须复合材料的力学性能都呈现出先增大后减小的趋势;混炼器混合的效果好于机械混合。EP/ZnO晶须复合材料的拉伸强度和冲击强度在混炼器混炼间隙为1 mm、ZnO晶须质量分数分别为5%和2%时取得最大值,分别为31.55 MPa和12 kJ/m2,相比同体系下的机械混合方式,EP/ZnO晶须复合材料的拉伸强度和冲击强度分别提高了14.3%和74.4%。继续增大混炼器混炼间隙会导致EP/ZnO晶须复合材料的力学性能变差。EP/ZnO晶须复合材料的导热系数随ZnO晶须含量的增加而增大,但混合方式对其影响不大;当ZnO晶须含量相同时,随着混炼器混炼间隙的增大,EP/ZnO晶须复合材料的导热系数有小幅增加。 相似文献
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研究了恒温陈化时间、搅拌时间对在高碱度条件下,以液相-恒温陈化法制备ZnO晶须的影响。结果表明,恒温陈化5h,搅拌时间为1.5~2h条件下,制备得到尺寸均一、结构规整、晶须产率都较高的ZnO晶须。 相似文献
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以工业氧化锌(ZnO)粉为原料,助剂以四钛酸钾(K_2Ti_4O_9)为主,采用助熔剂法制备大尺寸针状ZnO晶须,并对其生长条件及影响因素进行了研究。主要采用X粉末衍射仪,能谱仪和超景深显微镜机等分析手段对ZnO晶须的结构和形貌进行了表征并进行了简单的探讨。结果表明,当物料配比为C∶ZnO(5%Na_2B_4O_9·10H_2O)∶K_2Ti_4-O_9=0.60g∶0.50g∶3.00g,其中K_2Ti_4O_9粒径为10目,反应温度为900℃,恒温时间120min,坩埚容量30mL时,便得到纯度高、颜色白、形貌均一、针体长度约20mm的ZnO晶须。 相似文献
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本文采用四针状氧化锌晶须对RTM(树脂传递模塑)成型的玻璃纤维复合材料进行层间改性,从"离位"改性思想出发,将晶须直接引入到复合材料相对薄弱的层间部分,氧化锌晶须特殊的几何形状在层间部位形成刚性的机械"锚接"结构,这种物理而非化学的方式,能有效抑制复合材料的层间开裂及层间微裂纹的扩展,提高复合材料的层间剪切性能.研究结果表明,针对所选用的典型的航空用环氧树脂体系,氧化锌晶须的引入使复合材料的层间性能明显改善. 相似文献
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T-ZnO晶须增强环氧树脂复合材料的抗静电性 总被引:8,自引:0,他引:8
研究了T—ZnO晶须增强环氧树脂复合材料的抗静电性。结果表明:具有半导体性的T—ZnO晶须在复合材料中,相互搭接形成导电通路,以价带传导方式传导电荷,而起抗静电作用,使环氧树脂材料的体积电阻率降低了8个数量级,用比表面因子修正了网络形成临界体积分数模型。T—ZnO晶须的网络形成临界体积分数(0.057)是球形粒子的网络形成临界体积分数(0.38)的1/10。 相似文献
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《Journal of the European Ceramic Society》2007,27(12):3413-3424
Pure and Bi doped ZnO nanopowders have been prepared by a physical vapor deposition process in a solar reactor (SPVD). From X-ray diffraction (XRD) spectra performed on initial targets and on the nanopowders obtained, the lattice parameters and the phase changes as well as the average grain sizes and the grain shape anisotropies have been determined. High Resolution Transmission Electron Microscopy (HRTEM) observations support the results. The pure ZnO nanopowders “grain size” and “grain shape anisotropy” (whiskers with an average diameter of 20–40 nm) is a function of the air pressure during the vaporisation–condensation process: the higher the pressure, the longer the whiskers. The bismuth doped ZnO nanopowders are polyphased but the ZnO based majority phases behave similarly to pure ZnO with a tendency to form whiskers but with a grain size and grain shape anisotropy decreasing when the Bi content increases.Preliminary electrical measurements at temperatures below 300 °C have shown that the ionic conductivity of the nanocomposites obtained starting from ZnO + 23 wt% Bi2O3 targets is high and promising for applications. 相似文献
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在高碱度条件下,以液相-恒温陈化法制备出了形貌较好、纯度较高的ZnO晶须。用X射线衍射分析方法和扫描电子显微镜分别对其结构和形貌进行了表征。 相似文献
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Hongyu Wang Yolande Berta Gary S. Fischman 《Journal of the American Ceramic Society》1992,75(5):1080-1084
The microstructure of silicon carbide whiskers synthesized by carbothermal reduction of silicon nitride has been studied using transmission electron microscopy. All of the whiskers examined are single crystals, and grow in the (111) crystallographic direction. Two different forms of stacking faults and microtwins were observed; in one the planar defects are normal to the whisker growth direction, and the other has the defect planes at an angle of about 70° to the growth axis, while both forms of the defects are on the [111] closed-packed planes. Without the addition of catalyst, droplets containing metallic impurities were not found at the tips of the whiskers synthesized by the present process. A core and outer regions were observed in the single-crystal whiskers, which may be evidence that the whiskers were formed by a two-stage mechanism. 相似文献
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以陈化锌粉为锌源,利用热蒸发方法制得高纯度ZnO一维晶须材料,并对反应体系的工艺参数如氮气流量、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进行研究。利用SEM对产物形态进行表征。结果表明:以陈化锌粉为锌源,当反应温度为1000~1100℃,通入氮气量为0.2 m3/h,保温时间为60 min时能制备出高规整率、高产率转化率及高长径比的ZnO一维纳米材料。 相似文献
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《Journal of the European Ceramic Society》2022,42(13):5984-5994
Mullite fibers/whiskers hierarchical structure materials (MFWs) were prepared via the three-stage method, i.e. seeds breeding, precursors introducing and whiskers growth. The mechanism of low-temperature in-situ synthesis of mullite whiskers during gas-phase reaction process has been discussed in detail. The seeds bred on mullite fibers (MFs) are the growth points and can effectively reduce the subsequent growth temperature of mullite whiskers (MWs). The precursors composed of aluminum source, silicon source and catalyst provided raw materials for whiskers growth. Under the heat treatment temperature of 800 °C, mullite seed grains were guided to in-situ transform into MWs. Moreover, MFWs fabricated via low-temperature in-situ growth mechanism on the MFs present low density (0.103–0.147 g/cm3) and ultralow thermal conductivity (0.0426–0.0514 W·m?1·K?1). Due to the lower whiskers growth temperature in this work than the ones in the most recent literatures, the three-stage method can be regarded as a viable strategy for low-temperature in-situ growth whiskers. 相似文献
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氧化锌晶须表面改性及表征 总被引:13,自引:0,他引:13
采用湿法表面化学改性法,用硅烷和钛酸酯偶联剂对氧化锌晶须(ZnOw)进行了表面改性;考察了溶剂、pH值、温度及分散时间对硅烷类偶联剂改性效果的影响,采用活化指数、接触角以及傅立叶变换红外光谱对改性结果作了表征。同时将改性后的ZnOw填充到线性低密度聚乙烯(LLDPE)中,测试了复合材料的机械性能。实验结果表明,硅烷和钛酸酯偶联剂均能用于ZnOw的表面改性,其最佳改性条件不同,获得最佳改性效果的偶联剂用量也不同。经ND-42改性的ZnOw填充到LLDPE中,复合材料的弯曲强度大幅度提高。 相似文献