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以纳米α-Al2O3和Fe(NO3)3·9H2O为原料,采用非均相沉淀法制备了Fe包裹Al2O3的纳米复合粉体.经XRD、SEM分析发现:复合粉体前驱体经500 ℃焙烧,在H2中700 ℃还原可以得到纳米Fe包裹Al2O3的纳米复合粉体.粉体分散良好,Al2O3表面的纳米Fe粒子呈非连续状态,颗粒为球形,尺寸为30 nm左右,分布均匀.将复合粉体在热压下(30 MPa)烧结获得Al2O3/Fe复合陶瓷,当加入5mol%Fe时,陶瓷的热压烧结温度比单相Al2O3陶瓷降低将近100 ℃.含量为10mol%Fe的陶瓷样品在1500 ℃热压烧结后,断裂韧性可达到5.62 MPa,与相同条件下烧结的单相Al2O3陶瓷(KIc=3.57 MPa)相比提高了近57%. 相似文献
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本实验采用机械合金化工艺结合热处理工艺制备Fe3Al金属间化合物粉末,并将Fe3Al粉末与Al2O3粉末相混合制备Fe3Al/Al2O3复合粉末,并通过热压烧结工艺制备Fe3Al/Al2O3复合材料块材试样,对Fe3Al/Al2O3复合材料的物相组成,显微结构和力学性能进行研究.结果表明采用机械合金化工艺球磨60h后得到Fe-Al金属间化合物粉末.并经过800℃和1000℃热处理后得到Fe3Al金属间化合物粉末.经过热压烧结后得到的Fe3Al/Al2O3复合材料块材主要有Fe3Al相和Al2O3相.Fe3Al/Al2O3复合材料的显微结构均匀致密.Fe3Al晶粒均匀分布在Al2O3基体中,Fe3Al晶粒的平均颗粒尺寸为3~4μm,而Al2O3基体颗粒尺寸为4~5 μm.随着基体中Fe3Al合金含量的增加,Fe3Al/Al2O3复合材料的密度和相对密度逐渐增加;Fe3 Al/Al2O3复合材料的抗弯强度和断裂韧性逐渐增加;Fe3Al/Al2O3复合材料的洛氏硬度和弹性模量逐渐降低.Fe3Al/Al2O3复合材料具有较高的力学性能是由于复合材料具有均匀致密的显微结构. 相似文献
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氧化铝基纳米复合陶瓷显微结构的研究 总被引:18,自引:2,他引:16
考察了Al2O3-SiC和Al2O3-ZrO2(3Y)-SiC纳米复合陶瓷的断裂方式。由于SiC的加入,材料以穿晶断裂为主。通过透射电镜观察,研究了纳米复合陶瓷中材料SiC颗粒的分布,证明所制备的材料为晶内型纳米复合陶瓷。在Al2O3-ZrO3(3Y)-SiC纳米复合陶瓷中,小的ZrO2颗粒分布于Al2O3晶粒内,大的ZrO2晶粒位于Al2O3晶粒间,ZrO2的分布影响Al2O3晶粒的形状。通过高分辨透射电镜,观察了Al2O3-SiC和Al2O3-ZrO2(3Y)-SiC纳米复合陶瓷中Al2O3/Al2O3,Al2O3/SiC,Al2O3/ZrO2的界面。在两颗晶粒间的晶界几乎没有玻璃相的存在,证明纳米复合材料中晶界得到了加强,有利于力学性能的提高。 相似文献
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轧制复合-粉末冶金发泡工艺制备泡沫铝夹心板 总被引:1,自引:0,他引:1
针对目前泡沫铝夹心板制备工艺中存在的主要问题,将轧制复合技术应用于可发泡复合板的制备,以获得更高的芯层粉末致密度与界面结合强度. 研究结果表明,预压成型后的芯层粉体通过轧制过程能够同钢面板实现牢固的初结合,轧后芯层粉末的致密度明显高于热压复合板,粉末颗粒间呈紧密的层片状结构,为发泡过程创造了有利条件. 综合考虑界面结合强度、芯层粉末致密度及轧制缺陷等因素,轧制压下率应控制在60%~70%为宜. 复合板在适宜的发泡工艺下可以获得理想的泡沫体结构,最佳发泡温度为620~640℃,发泡时间为8~10 min. 发泡后在界面上生成了厚度均约为10 μm的金属间化合物FeAl3及Fe/Al固溶体,无脆性金属间化合物Fe2Al5生成,界面形成了理想的冶金结合. 相似文献
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ZrB2-Al2O3复合粉体的自蔓延高温还原合成与表征 总被引:7,自引:0,他引:7
用自蔓延高温还原合成制备了ZrB2-Al2O3复合粉体。用X射线衍射仪、扫描电镜和透射电镜等分析测试手段,对所制得的复合粉体的相组成、相貌及微观组织进行了表征。结果表明:ZrB2和Al2O3以主晶相的形式存在于复合粉体之中,二者存在良好的界面结合,这主要与ZrB2在Al2O3颗粒表面结晶生长有关。 相似文献
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为了制备具有纳米多孔结构的磁性复合微球,采用正硅酸四乙酯(TEOS)和金属氯盐分别作为SiO2和铁氧体的前驱体,通过溶胶凝胶法制备将Fe3O4纳米颗粒分散于SiO2基体中的Fe3O4/SiO2磁性纳米复合微球,并用超临界干燥法对其进行干燥。利用X线衍射(XRD)、红外光谱(IR)、透射电镜(TEM)和振动试样磁场计(VSM)等分析测试手段对合成的材料进行性能表征。结果表明:复合粒子包覆完好、性能优良、分散性良好,制备颗粒的粒径为30 nm,比饱和磁化强度为84.09 A.m2/kg。 相似文献
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聚合物乳液法表面修饰改性Fe_3O_4磁性纳米粒子特性研究 总被引:2,自引:0,他引:2
探讨了一种聚合物乳液在机械搅拌下,改性修饰Fe3O4纳米粒子表面,制备Fe3O4-聚合物复合粒子的方法。含羧基基团的柔软的聚合物乳胶粒子在机械搅拌作用下,与Fe3O4纳米粒子碰撞,变形,并通过物理粘附及羧基活性基团的化学吸附作用来包覆Fe3O4纳米粒子。在透射电子显微镜下可看到Fe3O4粒径约为5~20 nm,被聚合物包覆,虽存在团聚,但团聚体尺寸也仅100 nm左右,且团聚体中的Fe3O4纳米粒子也为聚合物隔开,纳米粒子得到了良好的分散。通过红外、热失重、接触角等的测试分析,进一步证实乳液聚合物对Fe3O4纳米粒子实现了表面修饰。实验结果表明,改性用聚合物的Tg以及复合温度是影响聚合物对Fe3O4纳米粒子包覆的重要因素之一。 相似文献
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用于靶向抗癌药物微球的磁性Fe3O4颗粒必须具有合适的粒径,并且保证其不发生团聚。采用化学共沉淀法制备了纳米Fe3O4磁性颗粒,XRD分析证实了产物的主要组成为立方晶系Fe3O4;粒度分析表明,产物平均粒径16.3 nm左右,粒径分布宽度约5.8 nm;采用高分辨透射电镜(HRTEM)观察产物形貌,证明纳米Fe3O4胶体溶液中磁性粒子呈球形分布,且未发生明显的团聚现象;测得Fe3O4胶体溶液ζ电位为+39.9 mV,颗粒吸附溶液中的C l-离子形成了吸附双电层结构,较强的静电排斥力阻止纳米粒子团聚,因此,制得的纳米Fe3O4胶体溶液具有很强的分散稳定性。 相似文献
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以聚酰胺酸为炭膜前驱体,分别以Fe_3O_4、γ-Fe_2O_3、Zn_(0.5)Ni_(0.5)Fe_2O_4以及二茂铁为掺杂物,经高温热解制备了4种Fe系物质掺杂的气体分离功能炭膜,对所制备的功能炭膜微结构及磁性能进行了表征.结果表明,各掺杂物在热解炭化过程中发生了物相结构的变化,其中Fe_3O_4和Zn_(0.5)Ni_(0.5)Fe_2O_4纳米粒子对前驱体起到了催化石墨化的作用.气体渗透测试结果表明,各掺杂物所制备的功能炭膜以分子筛分机理为主导进行气体分离,且气体渗透性能都有了显著的提高,特别是小分子气体H2渗透性最大提高了近48倍,Fe3O4掺杂所制备的功能炭膜,其H_2、CO_2、O_2、N_2和CH_4等单组分气体的渗透系数分别达到了12 194、3 433、1 175、136和74 Barters[1Barter=1×10~(-10)cm~3(STP)·cm/cm~2·s·cmHg].经FeO_4、γ-Fe_2O_3和Zn_(0.5)Ni_(0.5)Fe_2O_4掺杂制备的功能炭膜更是提高了H_2/CO_2的分离选择性. 相似文献
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Tin Oxide Nanoparticle-Functionalized Multi-Walled Carbon Nanotubes by the Vapor Phase Method 总被引:2,自引:0,他引:2
The vapor phase method was used to prepare tin oxide (SnO2 )-functionalized multi-walled carbon nanotubes (MWNTs). SnO2 nanoparticles were uniformly decorated on the outer surface of MWNTs. At the same time, parts of the MWNTs can be filled with SnO2 nanoparticles. This simple technique is of interest for a distinct reacting process and efficiency. 相似文献
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Hyonkwang Choi Jaeseok Gong Yeongjin Lim Ki Hong Im Minhyon Jeon 《Nanoscale research letters》2013,8(1):110
We studied the effects of the electrical conductivity and orientation of silicon substrate on both catalytic Fe thin film and the structure and morphology of multi-walled carbon nanotube (MWNT) grown by low-pressure chemical vapor deposition. Both p-type Si(100) and Si(111) substrates with three different doping concentrations (high, low, undoped) were used to evaluate the formation of catalytic nanoparticles and the growth of MWNTs. The morphology of catalytic nanoparticles such as size and density was characterized by field-emission scanning electron microscopy, Cs-corrected energy-filtered transmission electron microscopy, and X-ray photoelectron spectroscopy. Structural characteristics of MWNTs grown on different combinations of silicon substrate orientation and electrical conductivities (σ) were also systematically analyzed. Based on the experimental results, growth modes of MWNTs could be controlled by choosing an appropriate combination of σ and orientation of Si substrates. 相似文献
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Carbon nanotubes (CNTs) modified with semiconductor nanocrystalline particles may find wide applications due to their unique properties. Here Cadmium Sulfide (CdS) nanoparticles were successfully grown on Multi-Walled Carbon Nanotubes (MWNTs) via a magnetron sputtering method for the first time. The CdS/MWNTs sample was characterized with X-ray diffraction (XRD), Field Emission Scanning and High Resolution Transmission Electron Microscopies (SEM/TEM) and four point probe. The obtained images show clearly the decoration of the MWNTs by the CdS nanoparticles, and the XRD measurements indicate the CdS structure as hexagonal type. Moreover, the physical properties of the CdS/MWNTs were compared with the physical properties of the CdS nanoparticles grown on the silicon. Electrical measurements of CdS and CdS/MWNTs reveal that CdS/MWNTs has lower resistivity than the CdS sample which may be due to the higher carrier concentrations. 相似文献
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ABSTRACT: A low-temperature, direct blending procedure was used to prepare composite films consisting of zinc oxide [ZnO] nanoparticles and multiwalled carbon nanotubes [MWNTs]. The mesoporous ZnO/MWNT films were fabricated into the working electrodes of dye-sensitized solar cells [DSSCs]. The pristine MWNTs were modified by an air oxidation or a mixed acid oxidation treatment before use. The mixed acid treatment resulted in the disentanglement of MWNTs and facilitated the dispersion of MWNTs in the ZnO matrix. The effects of surface property and loading of MWNTs on DSSC performance were investigated. The performance of DSSCs was found to depend greatly on the type and the amount of MWNTs incorporated. At a loading of 0.01 wt%, the acid-treated MWNTs were able to increase the power conversion efficiency of fabricated cells from 2.11% (without MWNTs) to 2.70%. 相似文献