纤维表面处理对CF/PAA复合材料界面性能的影响

采用多结构形态倍半硅氧烷（VMS—SSO）涂层结合等离子活化纤维表面的方法对碳纤维（CF）改性,研究了纤维表面处理对碳纤维／聚芳基乙炔复合材料界面性能的影响．结果表明,等离子活化前后纤维表面涂层处理使材料的ILSS分别提高25％和45％,在碳纤维与树脂之间引入了过渡层．等离子活化纤维在碳纤维与涂层间通过VMS-SSO引入了化学键连接．含活性官能团的多形态倍半硅氧烷涂层在等离子活化纤维前后处理碳纤维,都能提高复合材料的界面性能．但是效果不同．其原因是,碳纤维与树脂间相互作用的不同,前者主要是过渡层效应,后者在碳纤维与树脂间引入了化学键．     

聚合物涂层对高模量碳纤维表面性能的影响

为改善碳纤维表面性能以及碳纤维/树脂复合材料的界面性能,对PAN基高模量碳纤维（HMCF）表面进行聚合物涂层处理。研究了不同潜伏性固化剂含量的聚合物涂层对HMCF表面以及碳纤维/树脂复合材料的界面性能的影响。IR分析表明,聚合物涂层与纤维或树脂基体发生了化学反应。扫描电镜和动态机械热分析的结果也说明,聚合物涂层能够提高...     

碳纤维涂覆SiC新工艺及涂层纤维的力学特性

用气相SiO和CO反应形成SiC的方法成功地在碳纤维上涂覆SiC.SiC涂层是由β-SiC团粒从碳纤维表面向外生长形成,并具有玉米棒子状的表面形貌。SiC层厚度增加到≥0.2μm,涂层纤维的拉伸强度随SiC层厚度增加而下降,此结果与Ochiai的理论模型相吻合。SiC层厚度达到1μm的涂层纤维,其拉伸时的力学行为与具有弱界面结合的1维脆性纤维-脆性基质复合材料相似,并显示SiC层的多次断裂。对碳纤维芯因涂层处理而引起的性能退化进行了讨论。      

铜钴镍铁氧体/聚苯胺复合物的制备及其电磁性能

采用水热法制备铜钴镍铁氧体粉末,通过原位聚合法制备具有改善电磁屏蔽性能的铜钴镍铁氧体/聚苯胺复合材料.通过X射线衍射(XRD)、扫描电子显微镜(SEM)和热失重分析仪(TG)来表征该复合材料的形态和结构.研究结果表明,聚苯胺均匀包覆铜钴镍铁氧体,与原始的铜钴镍铁氧体和聚苯胺相比,铜钴镍铁氧体/聚苯胺复合材料显示出增强的屏蔽效果.当铜钴镍铁氧体含量为40％、涂层厚度为2.5 mm时,铜钴镍铁氧体/聚苯胺复合材料的最佳屏蔽效果达到-50 dB,这表明铜钴镍铁氧体/聚苯胺复合材料具有良好的电磁性能.     

铜纤维含量对碳纤维/铜纤维混编增强酚醛树脂基复合材料制备及摩擦性能的影响

以碳纤维和铜纤维为原料制备了三维四层深交联机织物,将酚醛树脂和其他填料组成树脂体系,并与深交联机织物复合成型,制成碳纤维/铜纤维混编增强酚醛树脂基复合材料。通过测定预制件孔径和复合材料的密度、孔隙率,研究了不同铜纤维含量对树脂基复合材料制备的影响,并对样品进行了测试。研究结果表明:在一定范围内,随着铜纤维含量的增加,预制体与基体复合较好,摩擦表面较为平整。随着铜纤维含量增加,复合材料的摩擦系数及磨损量随之增加。磨损形式主要以磨粒磨损为主。在纬纱中铜纤维单丝根数为5根条件下,制得的复合材料的孔隙率为2.4%,平均孔径为80.8676μm,摩擦系数为0.2355。     

增强纤维的梯度功能涂层

本文在分析纤维增强金属基复合材料的纤维/基体界面的行为以及对增强纤维涂层的要求的基础上,提出能满足抗扩散,反应障垒、润湿媒介和保证纤维发挥潜能等多种要求的纤维涂层结构--梯度功能涂层.本文还介绍了用化学气相沉积(CVD)的方法在碳纤维上制备梯度功能涂层的细节.      

镍涂层短碳纤维增强AZ91D镁基复合材料的界面特征和阻尼性能

使用表面化学镀镍的短碳纤维为增强体、AZ91D粉为基体金属,用粉末冶金法和热挤压工艺制备镁基复合材料,用SEM、TEM-EDS、拉伸和动态热机械分析(DMA)等手段表征其微观形貌、界面结构、力学性能和阻尼性能,研究了金属镍涂层短碳纤维对AZ91D镁基复合材料的界面和阻尼性能的影响。结果表明,碳纤维在复合材料中分布均匀,沿着挤压方向定向排列;镍涂层改善了碳纤维与AZ91D基体之间的润湿性;不同频率的应变谱和G-L特征线都表明:复合材料的阻尼机制,除了位错之外还有其他机制;随着应变频率的提高复合材料的阻尼机制由以界面滑移为主转变为以位错为主。随着温度的升高涂层碳纤维增强镁基复合材料的阻尼容量增大,在250~300℃出现一个阻尼峰。随着频率的提高阻尼峰值的温度移向高温,表现出热激活弛豫过程的特征,根据Arrhenius公式计算出其热激活能(H)为3.448 e V。     

Al2O3涂层碳纤维/环氧基复合材料的性能研究

采用溶胶-凝胶法在碳纤维的表面涂覆了一层Al2O3涂层,透射电镜分析表明涂层中粒子的大小约为10nm,接触角分析表明涂层后碳纤维的表面张力有大幅提高.通过比较涂层前后碳纤维/环氧复合材料的力学性能发现,Al2O3涂层后复合材料的层间剪切强度,拉伸强度和弯曲强度分别提高了17.7%,4.8%和3.1%.扫描电镜分析表明,Al2O3涂层后的碳纤维与环氧树脂基体的结合更加紧密.且在碳纤维表面形成的Al2O3涂层在350℃～700℃能有效地减缓碳纤维环氧基复合材料的氧化失重速率.     

CF表面低聚倍半硅氧烷涂层对复合材料界面性能影响

采用不同倍半硅氧烷(SSO) ( YGO-SSO 和Methacryl isobutyl-POSS) 涂层对碳纤维(CF) 改性, 有效地提高了碳纤维/ 聚芳基乙炔(CF/ PAA) 的层间剪切强度( ILSS) 。采用原子力显微镜(AFM) 以力调制模式对CF/ PAA复合材料横截面进行表面形貌和硬度分布研究, 通过对硬度图像进行统计学分析得到纤维、界面相、基体相硬度分布直方图和线分布图, 对不同涂层、同种涂层不同浓度改性后的复合材料界面相特性进行了比较和研究。结果表明, 不同结构、不同浓度SSO 涂层处理对界面的改性效果不同, 含大有机官能团的笼型倍半硅氧烷(MethacrylisobutylPOSS) 的改性效果好。AFM 分析直观地表明, 经不同结构SSO 涂层处理后CF/ PAA 复合材料中出现不同形貌结构、不同硬度的界面过渡层,该界面层提高纤维/ 树脂的粘接。      

碳纤维及其复合材料的新进展

本文简要介绍先进复合材料对发开高技术和新一代武器装备的重要意义,美国国防部已把复合材料收入国防关键技术计划.碳纤维是发展复合材料的基础,对碳纤维的发展国外给予高度重视,每年取得很多进展.本文介绍近年来碳纤维与复合材料的新进展,包括:高模、高强碳纤维及其复合材料;混杂纤维及其复合材料;纤维/聚亚胺颗粒;隐身用的特种碳纤维.     

Microstructure and mechanical properties of Al–2Mg alloy base short steel fiber reinforced composites prepared by vortex method

Fabrication and characterization of cast Al–2Mg alloy matrix composites reinforced with short steel fibers are dealt with in the present study. Three types of steel fiber were used: uncoated, copper coated and nickel coated. All the composites were prepared by the liquid metal route using vortex methods. When tested in tension, all composites exhibited improvement in strength due to high relative strength of steel fibers. The ductility was lowered except for the composite with copper coated fibers. Copper coated fiber reinforced composites gave the highest strength. Higher strength accompanied with appreciable ductility demonstrated by composites with copper coated fibers is attributed to the solid solution and fiber strengthening as well as good bonding at the interface. Composites reinforced with uncoated and Ni coated steel fibers did not exhibit strengthening to the level exhibited with copper coated fibers because brittle intermetallic phases are formed at the interface. These phases promote initiation and facilitate propagation of cracks. The observed fracture mechanism of composites was dimple formation, fiber breakage and pullout of fibers. Fracture surface of uncoated and Ni coated composites showed extensive pull out of fibers as well as fiber breakage confirming the above inference. In case of the copper coated composites dimple formation and coalescence was more extensive. EDX analysis showed a build up Cu, Ni, and Fe at the interface.     

硅酸铝短纤维增强镁基复合材料的界面反应及其热力学分析

用晶化的硅酸铝短纤维作增强体, 用磷酸铝作黏结剂制得预制体, 用AZ91D作基体金属, 通过挤压浸渗工艺制备镁基复合材料。通过光学显微分析、 XRD衍射分析、 SEM扫描分析等, 初步观察研究了硅酸铝短纤维增强镁基复合材料的界面反应规律和反应产物。结果表明: 用硅酸铝短纤维增强AZ91D镁合金通过浸渗挤压法制备镁基复合材料是可行的; 镁与磷酸铝黏结剂反应后在界面上生成一定数量的MgO颗粒和少量的MgAl₂O₄颗粒, 致使硅酸铝增强纤维和镁合金基体之间形成较强界面结合; 另外, 在硅酸铝短纤维的晶化处理过程中, 由于非晶态SiO₂的析出, 导致Mg₂Si脆性相在界面附近产生, 从而对该复合材料的力学性能产生一定影响。      

Mg-Mg2Si-MgO复合材料的反应自组织合成机理

以纯Mg粉,SiO2粉为原料,采用反应自组织生长的方法制备了以MgO,Mg2 Si为增强相的镁基复合材料.通过对试样的差热分析发现,Mg与SiO2在510～600℃之间发生原位化学反应,生成MgO与Si,被还原的Si继而与过量的Mg反应生成Mg2Si.采用扫描电镜和能谱分析对烧结后试样的微观形态进行分析,结果表明,经超...     

C/Al复合材料中镍涂层的界面行为

为改善纤维与基体的润湿性,在碳纤维表面涂覆Ni、SiC-Ni。经铝液浸渗实验表明Ni涂层可以使纤维很好地分布于基体中。但Ni单涂层导致碳纤维损伤,Ni、SiC-Ni两状态下界面与基体中均产生大量脆性相,急剧降低复合材料的强度。     

A facile synthesis of Cu(2)O/SiO(2) and Cu/SiO(2) core-shell octahedral nanocomposites

We report here a simple approach to the synthesis of Cu(2)O/SiO(2) core-shell nanocomposites in water solution. The Cu(2)O cores have a perfect octahedral structure with uniform size of about 200-300?nm. A compact SiO(2) shell 9?nm in thickness is located at the surfaces of Cu(2)O octahedra, and it is composed of fine SiO(2) nanoparticles. During the depositing of the SiO(2) particles, as we presumed, dynamic absorbing and disengaging of Na(+) at the interface of Cu(2)O octahedra and the solution made it possible for the formation of Cu-O-Si bonds between core and shell in the composites. The existence of Cu-O-Si bonds in our core-shell composite can be substantiated by peak changes at?1236 and 1080?cm(-1) in the FT-IR spectra. This is the reason why the SiO(2) shell is so compact and uniform. Moreover, these Cu(2)O/SiO(2) core-shell octahedra were further used as precursors, depending on a simple disproportionation reaction of Cu(2)O in acid, to easily achieve Cu/SiO(2) movable multicore-shell octahedral nanocomposites. In the final Cu/SiO(2) core-shell composite, the thin SiO(2) octahedral shell was held, inside of which formed several free Cu nanoparticles 50-80?nm in size. Studies on the Cu(2)O/SiO(2) core-shell octahedral composites and Cu/SiO(2) movable multicore-shell octahedral nanocomposites would be a good thing not only for fundamental research but also for applications.     

C/Al复合材料中镍涂层的界面行为

为改善纤维与基体的润湿性,在碳纤维表面涂覆Ni、SiC-Ni。经铝液浸渗实验表明Ni涂层可以使纤维很好地分布于基体中。但Ni单涂层导致碳纤维损伤,Ni、SiC-Ni两状态下界面与基体中均产生大量脆性相,急剧降低复合材料的强度。      

SiO2/Mg（OH）2复合阻燃剂的阻燃性能研究

以SiO2/Mg(OH)2复合粉体为阻燃剂,与聚烯烃弹性体(POE)熔融共混制备了复合材料,采用灼热丝试验对其阻燃性能进行了测试,利用SEM和EDS观察POE复合材料的断面形貌、界面相容性及阻燃剂在基体中的分散行为,并对POE复合材料的力学性能进行了测试。结果表明SiO2/Mg(OH)2复合阻燃剂在POE中分散良好,界面相容性优良,具有良好阻燃效果,且可改善聚合物材料力学性能,是一种适宜推广的新型无机阻燃剂。     

Microstructure evolution and elemental diffusion of SiCp/Al–Cu–Mg composites prepared from elemental powder during hot pressing

15vol%SiCp/Al–Cu–Mg composites were fabricated by hot pressing method using pure elemental powders. Microstructure evolution and elemental diffusion of Cu and Mg were studied. The microstructure of as-hot pressed composites and the elemental distribution of the composites before and after solution treatment were also investigated. The results showed that there were two types of eutectic liquid phases with different compositions after the compact was heated to 580 °C. After the compact was held at 580 °C for 60 min, the eutectic liquid was absorbed into the Al matrix and some equilibrium liquid phases formed in the boundaries of the initial Al particles. Meanwhile, Cu was homogeneously distributed in the Al particles while Mg tended to be distributed near the boundaries of the initial Al particles and in the SiC clusters. The presence of Al₂Cu, Mg₂Si, and some oxides of Mg was identified in the as-hot pressed composite. After solution treatment, Al₂Cu dissolved into the Al matrix, however, some Mg-rich compounds (silicide and oxide of Mg) did not dissolve into the matrix completely.     

Evaluation of the role of Au in improving catalytic activity of Ni nanoparticles for the formation of one-dimensional carbon nanostructures

In situ dynamic imaging, using an environmental transmission electron microscope, was employed to evaluate the catalytic activity of Au/SiO(2), Ni/SiO(2), and Au-Ni/SiO(2) nanoparticles for the formation of one-dimensional (1-D) carbon nanostructures such as carbon nanofibers (CNFs) and nanotubes (CNTs). While pure-Au thin-film samples were inactive for carbon deposition at 520 °C in 0.4 Pa of C(2)H(2), multiwalled CNTs formed from Ni thin films samples under these conditions. The number of nanoparticles active for CNF and CNT formation increased for thin films containing 0.1 mol fraction and 0.2 mol fraction of Au but decreased as the overall Au content in thin films was increased above 0.5 mol fraction. Multiwalled CNTs formed with a root growth mechanism for pure Ni samples, while with the addition of 0.1 mol fraction or 0.2 mol fraction of Au, CNFs were formed via a tip growth mechanism at 520 °C. Single-walled CNTs formed at temperatures above 600 °C in samples doped with less than 0.2 mol fraction of Au. Ex situ analysis via high-resolution scanning transmission electron microscopy (STEM) and energy-dispersive X-ray spectroscopy (EDS) revealed that catalytically active particles exhibit a heterogeneous distribution of Au and Ni, where only a small fraction of the overall Au content was found in the portion of each particle actively involved in the nucleation of graphitic layers. Instead, the majority of the Au was found to be segregated to an inactive capping structure at one the end of the particles. Using density-functional theory calculations, we show that the activation energy for bulk diffusion of carbon in Ni reduces from ≈1.62 eV for pure Ni to 0.07 eV with the addition of small amounts (≈0.06 mol fraction) of Au. This suggests that the enhancement of C diffusion through the bulk of the particles may be responsible for improving the number of particles active for nucleating the 1-D carbon nanostructures and thereby the yield.     

Cu的添加对Mg2Ni合金储氢性能的影响

采用机械合金化法,制备了Mg2Ni1-xCux(x=0、0.1、0. 3)合金,研究了Cu对Mg2Ni储氢合金储氢性能的影响.XRD和SEM研究表明Cu的加入使合金中产生了Cu11Mg10Ni9新相.利用PCT测试仪测定了合金的储氢性能,结果表明,添加Cu元素会降低合金的吸氢量,但能有效地提高放电容量和循环稳定性.制备出的Mg2Ni0.9Cu0.1与Mg2Ni0.7Cu0.3相比,前者具有较大的吸氢量,后者的放电容量较大,循环稳定性较好.