微波合成WCx/MWCNTs及其电催化性能研究

目的制备多壁碳纳米管负载碳化钨的纳米复合材料(WC_x/MWCNTs),探索微波加热温度对WC_x/MWCNTs合成的影响规律。方法利用分子自组装技术与微波加热技术相结合,以钨酸钠为W源,制备了WC_x/MWCNTs纳米复合材料。采用X射线衍射(XRD)和透射电子显微镜技术(TEM)对不同条件下制得样品的物相组成、结构及微观形貌进行了表征;采用循环伏安法在酸性环境下测试了WC_x/MWCNTs对氢和CH3OH的电催化性能。结果当微波加热温度为1000℃时,制备的WC_x/MWCNTs纳米复合材料由WC、WC2和C组成,碳纳米管的多壁结构保留较好,碳化钨颗粒均匀地分布在碳纳米管外表面,粒径为20~50 nm。循环伏安测试结果表明,制备的WC_x/MWCNTs在酸性环境下对氢具有一定的催化作用,但对甲醇没有明显的电催化作用。结论通过控制合理的微波加热温度,可制备出碳化钨粒径小、分布均匀、碳纳米管多壁结构完好的WC_x/MWCNTs纳米复合材料。制备的WC_x/MWCNTs在酸性环境下对氢具有一定的催化作用,可作为催化剂载体来负载其他金属制备复合催化剂。     

多壁碳纳米管复合BiSbTe材料的热电性能

研究了BiSbTe/多壁碳纳米管(MWCNTs)复合材料的球磨法制备及其热电性能(300~500 K)。采用商用BiSbTe块体作为基体材料,利用球磨及压力辅助的感应加热烧结进行致密化得到了不同复合比的BiSbTe/0.5、1.0 vol% MWCNTs复合材料。复合MWCNTs后,引入的纳米复合结构增强了声子散射,大幅降低了热导率,同时由于载流子散射的增强和较低的致密度使电导率恶化。尽管电导率降低但热导率得到抑制,BiSbTe/1.0 vol% MWCNT复合材料的热电优值与BiSbTe基体接近。结果表明,优化加工参数获得更高的致密度可以优化BiSbTe/MWCNTs复合材料的热电性能。     

一种新型MWCNTs/氟碳漆防腐蚀导电涂层

为了解决现有石油化工企业防腐蚀导电涂料存在的防腐蚀性能低、耐磨性差、涂层易溶胀溶解的问题,选取耐蚀性好、耐磨性优良的氟碳涂料为基料,添加碳纳米管为填料制备了新型防腐蚀导电材料。通过表面粗糙度测试、力学性能测试、电化学阻抗谱(EIS)和傅里叶变换红外光谱(FTIR)技术,研究了多壁碳纳米管(MWCNTs)的加入对氟碳漆涂层表面粗糙度、力学性能、紫外老化以及化学结构的影响。结果表明:MWCNTs/氟碳漆防腐蚀导电涂层跟纯氟碳漆涂层相比表面粗糙度变化不大,拉伸强度和弹性模量分别增大了150%和133%,紫外加速老化24,72,144,216h后的耐蚀性也有所增强,MWCNTs不影响氟碳漆的化学结构。     

多壁碳纳米管/氧化铕复合材料的制备

利用混合酸对催化裂解法制备的多壁碳纳米管进行纯化,然后先后用氨水和柠檬酸对纯化后的多壁碳纳米管进行修饰,最后利用共沉淀法和热处理制各了碳纳米管氧化铕复合材料,并使用红外光谱、X-衍射仪(XRD)、扫描电镜(SEM)研究了碳纳米管及氧化铕复合材料的结构和形貌.光谱结果表明:经过混合酸纯化后,碳纳米管表面拥有丰富的羟基和羧基等官能团,而且能够在纯化后的多壁碳纳米管表面引入氨基和柠檬酸分子.电子显微图像显示,在450℃下热处理,获得了多壁碳纳米管/氧化铕纳米线复合材料;在750℃下热处理,获得了多壁碳纳米管/纳米氧化铕复合材料.     

碳纳米管增强银复合材料的导热性(英文)

通过分子水平层级混合制备了碳纳米管增强银基复合材料。研究了碳纳米管的类型(单壁/多壁)及功能化模式(共价键/非共价键)对银复合材料导热性的影响。XRD及EDS结果表明,复合材料中存在银与碳。高分辨率扫描电镜和透射电镜结果表明碳纳米管均匀地嵌在银基体中。利用拉曼光谱和FTIR研究了共价键功能化对多壁碳纳米管的影响。共价键功能化后,碳纳米管中引入了功能团且保持结构完整。利用激光闪光技术以及有效介质理论研究了复合材料的导热性。实验结果表明:加入共价功能化的单壁和多壁纳米碳管后,材料的导热性降低。但加入非共价键功能化的多壁碳纳米管后,复合材料的有效导热性增强,这与不考虑界面热阻时的有效介质理论预测结果一致。     

碳纳米管表面强化高强铝合金磨损性能研究

用搅拌摩擦加工(FSP)技术将多壁碳纳米管(MWCNTs)添加在LC9铝合金板表面,并在其表层形成碳纳米管铝基复合材料,表面强化高强铝合金材料.结果表明,MWCNTs的加入,可使铝基复合材料的耐磨性明显提高.随着MWCNTs含量的增加,复合材料的磨损量呈降低趋势,耐磨性能提高.在复合材料表面主要发生了磨粒磨损现象.     

聚多巴胺改性碳纳米管增强羧基丁腈橡胶动态力学性能的研究

目的 探究改性多壁碳纳米管（MWCNTs）在羧基丁腈橡胶（XNBR）中的分散性、增强橡胶基体动态力学性能及其作用机理。方法 采用多巴胺自聚合兼物理修饰的技术对MWCNTs进行表面改性处理，以增加其表面极性基团，提高其与XNBR基体的兼容性，并制备了聚多巴胺改性碳纳米管（MWCNTs-P）。采用红外光谱仪和X射线光电子能谱仪分析了改性多壁碳纳米管的表面化学状态，使用透射电子显微镜（TEM）探索了改性碳纳米管的结构演变。使用动态力学分析仪（DMA）研究了改性碳纳米管填料网络对XNBR基体的增强效果，结合复合材料断面的扫描电镜（SEM）和透射电镜（TEM），探索了MWCNTs-P填料增强XNBR动态力学性能的作用机理。结果 调控多巴胺反应浓度实现了MWCNTs-P填料表面物理包覆层厚度从2 nm增加到4 nm。动态力学性能测试表明，MWCNTs-P填料提高了复合材料老化前后的动态力学性能。SEM测试发现，MWCNTs-1.0P-2.0wt%复合材料在老化试验后断面存在的孔洞最浅。TEM测试发现，MWCNTs-1.0P填料在XNBR基体中有更好的分散性。结论 聚多巴胺改性多壁碳纳米提高了其在羧基丁腈橡胶基体中的分散性，从而增强了复合材料老化前后的动态力学性能。     

球形SiO2表面Ag纳米粒子生长及其拉曼增强效应

以聚乙烯吡咯烷酮(PVP)作为还原剂和稳定剂制备SiO2/Ag纳米复合材料,分析银氨络离子的浓度对银纳米粒子的影响,采用透射电镜(TEM)、扫描电镜(SEM)对SiO2/Ag复合材料进行表征,并研究以SiO2/Ag为基底的表面拉曼散射增强。结果表明,银纳米颗粒以多晶形式沉积在球形二氧化硅表面,通过调节银氨络离子的浓度可以改变Ag纳米颗粒的大小及其在SiO2上的沉积量;当银的沉积量增加时,表面拉曼散射也随之增强。     

MWCNTs/Zn0.96Co0.04O复合纳米纤维的电纺制备及其红外/雷达兼容隐身性能研究

混酸纯化多壁碳纳米管（MWCNTs），采用静电纺丝技术制备了MWCNTs /Zn0.96Co0.04O复合纳米纤维。采用TGA、XRD、FT-IR、SEM和TEM等手段对产物进行了表征；利用矢量网络分析仪和等IR-2红外发射率测试仪分别测试了产物的电磁参数和红外发射率，研究了MWCNTs的复合量对产物吸波性能和红外发射率的影响。结果表明:经600℃煅烧后得到的MWCNTs /Zn0.96Co0.04O复合纳米纤维直径约为160nm。当MWCNTs的质量分数为6%时，产物具有最低红外发射率为0.61；当匹配厚度为1.5mm时，产物在13.8GHz处最低反射损耗值为-26.4dB，小于-10 dB的吸收频段为11.8～15.8 GHz，有效吸收带宽为4.0GHz。这使得多壁碳纳米管/Zn0.96Co0.04O复合纳米纤维有望成为一种极具应用前景的红外/雷达兼容隐身材料。     

高体积分数MWCNTs/AZ80复合材料的显微组织

采用搅拌摩擦加工技术制备体积分数为19.5%的多壁碳纳米管(MWCNTs)增强AZ80镁基复合材料,研究经多道次搅拌摩擦加工(FSP)加工后复合材料的显微组织和MWCNTs在基体中的分布和稳定性,分析MWCNTs与基体的界面结构特征。结果表明:多道次FSP能提高MWCNTs在基体中的分散性,并在基体中形成了纳米晶,晶体尺寸仅5 nm左右。经多道次FSP后,MWCNTs在径向上的多壁结构未受到机械损伤,但经7道次加工后,在复合材料中发现有少量Al4C3相;碳纳米管与镁基体以半共格的界面形式相接。     

ECAP变形对MWCNTs/AZ31复合材料抗腐蚀性能的影响

采用碳纳米管孕育块铸造法制备多壁碳纳米管/AZ31镁基复合材料,经等径角挤压(ECAP)变形后对复合材料在3.5%NaCl(质量分数)的腐蚀介质中进行静态浸渍试验和电化学极化曲线测定,研究等径角挤压变形工艺对复合材料抗腐蚀性能的影响;利用数码相机、扫描电子显微镜对复合材料腐蚀前后的表面形貌进行观察和分析;并对复合材料的抗腐蚀机理进行分析。结果表明:等径角挤压变形工艺能有效的提高多壁碳纳米管(CNTs)/AZ31复合材料的抗腐蚀性能,经等径角挤压变形4道次后,复合材料的平均腐蚀速率由挤压态的0.6035mg/(m2·s)降为0.2963mg/(m2·s)。腐蚀电流密度Icorr由ECAP变形前的3.363μA/cm2减小到2.269μA/cm2。     

WMCNTs/AZ31复合材料电化学腐蚀研究

采用碳纳米管孕育块铸造法制备碳纳米管/AZ31镁基复合材料,测量其电化学极化曲线,研究碳纳米管加入量对复合材料抗腐蚀性能的影响,利用SEM对复合材料腐蚀前后的表面形貌进行了观察和分析。结果表明,碳纳米管的加入有效地提高了复合材料的抗腐蚀性能,随着复合材料中碳纳米管加入量的增加,腐蚀电流密度I_corr由5.279 μA/cm²减小到2.994 μA/cm²。     

Fabrication and mechanical properties of MWCNTs-reinforced aluminum composites by hot extrusion

Over the past decade,the interest in aluminum composites reinforced with carbon nanotubes has grown significantly.Studies have been carried out to overcome problems with uniform dispersion,interfacial bonding,void formation and carbide formation of the composites.In the present work,multi-wall carbon nanotubes(MWCNTs)aluminum composites were produced.High-energy ball milling with the aim at developing well-dispersed MWCNTs Al composites was followed by cold compaction,sintering,and hot extrusion at 500 ℃.Different amounts of stearic acid as processing control agent(PCA)is used in order to minimize cold welding of the Al particles,and to produce finer particles.Differential scanning calorimetry(DSC),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and X-ray diffraction(XRD)were employed to analyze the MWCNTs,the aluminum powder,and the composites' microstructural behavior.The hardness and tensile properties of the composites are also evaluated.The results showed 500％ increase in yield stress after the addition of 1 wt％ MWCNTs in Al-MWCNTs based composite.The ball-milling time of 4 h is found to be sufficient as excessive milling time destroys a vast number of MWCNTs.     

Effect of hydroxyapatite‐titanium‐MWCNTs composite coating fabricated by electrophoretic deposition on corrosion and cellular behavior of NiTi alloy

In this study, the hydroxyapatite (HA)‐titanium (Ti, 20 wt.%) multiwalled carbon nanotubes (MWCNTs, 1 wt.%) composite coating was applied on the NiTi alloy by using the electrophoretic deposition (EPD) technique. The morphologies and the phase structures of the coatings were investigated by the FESEM and XRD analysis, respectively. The corrosion behaviors of the coated NiTi samples were investigated using the polarization and electrochemical impedance spectroscopy tests in a simulated body fluid (SBF). The amounts of the released Ni ions from the coated NiTi were studied in the SBF. The results of the electrochemical tests revealed the corrosion resistance of the NiTi coated with HA was further improved by the addition of the Ti and MWCNTs to the HA coating. The current density and corrosion resistance of the NiTi alloy changed from 2.52 μA.cm^?2 and 24.13 kΩ to 0.91 nA.cm^?2 and 5.92 MΩ after coated with the HA‐Ti‐MWCNTs composite coating. Also, the number of nickel ions released from the surface of the NiTi alloy to the SBF medium suppressed from 11.8 to 0.08 μgr.L^?1, after coating with HA‐Ti‐MWCNTs. Also, the cellular proliferation in the culture medium consisting of the NiTi alloy coated with the HA‐Ti‐MWCNTs improved significantly (compared with that of the NiTi alloy) as shown no toxicity in the cell culture medium.     

Pseudocapacitive performance of hybrid manganese oxide films with multiwalled-CNT additions

In the present study, hybrid manganese oxide films with additions of multiwalled carbon nanotubes (MWCNTs) were prepared by sol-gel process. Manganese acetate was used as the precursors and MWCNTs were added during the process. The effects of MWCNT addition and post heat treatment on the material characteristics and pseudocapacitive performance of the hybrid MWCNT/MnO_x films were investigated. Experimental results showed that manganese oxide was composed of Mn₃O₄ (minor) and Mn₂O₃ (major) phases after heat treatment. MWCNTs served as the template for the growth of manganese oxide films. Among the hybrid films prepared in the present study, manganese oxide films with 0.05 wt.% MWCNT addition heat treated at 350 °C exhibited the best electrochemical performance. The maximum specific capacitance was 340.3 F/g and retained 280.8 F/g (82.5%) after 1000 CV tests. With the addition of MWCNTs, not only the specific capacitance increased but also the reliability improved.     

Conducting polymer functionalized multi-walled carbon nanotubes with noble metal nanoparticles: Synthesis,morphological characteristics and electrical properties

We report the synthesis of conducting polyaniline-functionalized multi-walled carbon nanotubes (MWCNTs-f-PANI) containing noble metal (Au and Ag) nanoparticles composites (MWCNTs-f-PANI-Au or Ag-NC). MWCNTs-f-PANI was initially synthesized by functionalizing acyl chloride terminated carbon nanotubes (MWCNTs-COCl) with 2,5-diaminobenzenesulphonic acid (DABSA) via amide bond formation, followed by surface initiated in situ chemical oxidative graft polymerization of aniline in the presence of the ammonium persulphate (APS) as an oxidizing agent. MWCNTs-f-PANI was then dispersed into an aqueous Au or Ag metal salt solution followed by the addition of sodium citrate, which acted as a reducing agent. The resulting composite contained a high level of well dispersed Au or Ag nanoparticles (MWCNTs-f-PANI/Au-NC or MWCNTs-f-PANI-Ag-NC). Morphological and structural characteristics, as well as electrical conducting properties of the hybrid nanocomposites were characterized using various techniques including high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–visible spectroscopy (UV–vis) and four-probe measurements. FT-IR spectra confirmed that PANI was covalently bonded to MWCNTs. TEM images revealed the presence of Au or Ag nanoparticles finely dispersed in the composites with a size of <15 nm. XRD analysis revealed the presence of strong interactions between the metal nanoparticles and MWCNTs-f-PANI, where the metal particles were present in a phase-pure crystalline state with face centered cubic (fcc) structure. The room temperature electrical conductivity of the MWNCTs-f-PANI/Au or Ag composites was 4.8–5.0 S/cm, respectively, which was much higher than that of CNTs-f-PANI (0.18 S/cm) or pure PANI (2.5 × 10^?3 S/cm). A plausible mechanism for the formation of nanocomposites is presented. We expect that the new synthesis strategy reported here will be applicable for the synthesis of other hybrid CNTs–polymer/metal nanocomposites with diverse functionalities. This new type of hybrid nanocomposite material may have numerous applications in nanotechnology, gas sensing, and catalysis.     

磁性Fe3O4/Ag复合纳米粒子制备与抗菌性能

采用箔-纤维-箔法和1150℃/150 MPa/30 min的真空热压工艺成功制备了SiCf/Ti-43Al-9V复合材料,并使用金相显微镜、X射线衍射仪、扫描电镜及能谱仪对该复合材料微观组织的形成进行了研究.结果表明,制备过程中SiC纤维与TiAl基体合金发生反应,并形成一定厚度的反应层;基体组织为等轴晶,粒径约为8 μm,与原始合金组织相比明显细化;从反应层到远处的TiAl基体合金,基体合金的组织由全γ相转变为α2/γ片层组织、γ晶粒和晶间B2相的混合组织.其中全γ相区域的厚度为2～4 μm,并围绕纤维分布.根据Ti-Al-V相图、C原子和V原子的扩散,分析了这两个基体区域的形成机理,并结合热压成形过程中的塑性变形和变形储存能,解释了基体合金晶粒大小的变化.     

离子液体辅助制备AgCl/Ag2O复合光催化剂

在离子液体[CPMIm]Cl辅助下,采用沉淀法原位制备了AgCl/Ag2O复合光催化剂。采用X射线衍射仪(XRD)、能量散射光电子能谱(EDS)、扫描电镜(SEM)、比表面仪(BET)和紫外-可见漫反射光谱(UV-Vis DRS)等对AgCl/Ag2O复合光催化剂结构、组成、形貌、比表面积和光吸收性能进行了表征;运用表面光电压谱(SPS)对异质结光催化剂的光生电荷分离特性进行了研究。考察了AgCl/Ag2O复合光催化剂对模拟污染物甲基橙的光催化降解性能。结果表明,AgCl的存在抑制了Ag2O颗粒的生长,增加了复合光催化剂的比表面积和孔容积。AgCl与Ag2O的原位复合有效提高了复合光催化剂光生e^-/h⁺对分离速率,增强了复合光催化剂对甲基橙的光催化降解。捕获测试表明?O2^-是光催化降解甲基橙的主要活性自由基。     

复合电沉积Ni-MWCNTs及镍电结晶的研究

研究了水平阴极方式复合电沉积Ni-MWCNTs(Ni-多壁碳纳米管).采用硫酸镍基础电解液,添加适当表面活性剂和光亮剂,MWCNTs为2～2.5 g/L,电流密度为2.5 A/dm2时,获得的Ni-MWCNTs沉积层结构致密,复合沉积层中MWCNTs含量达22.45%.复合电沉积层表面微观形貌照片显示,MWCNTs在复合电沉积层中占主要体积,镍的电结晶形态呈球形,结晶点位置位于MWCNTs管壁缺陷处及部分管端处,MWCNTs的管端和管壁缺陷处的Ni晶粒相互连接,形成牢固的复合沉积层.复合电沉积层中MWCNTs含量受电解液中MWCNTs浓度、电流密度以及光亮剂影响,在MWCNTs上的Ni沉积层连续性直接受MWCNTs管壁上缺陷的数量和连续性影响,形成晶核的缺陷尺度至少在1 nm以上.