石墨烯金属基复合材研究进展

本文详细叙述了石墨烯及其衍生物等增强相的应用范畴及适用区别以及比较了金属基复合材料的不同制备方法,分析传统的制备方法之间的分类特点及应用方向,重点提出了工艺步骤灵活、可控性极高的新型制备石墨烯增强金属基复合材料的方法—激光增材制造技术。深入讨论了石墨烯及其衍生物作为增强相,给金属基复合材料中带来的力学、摩擦学、电学、金属耐腐蚀等性能方面的改变,比较了石墨烯及衍生物作为增强相对铝、镁、镍、铜、钛等金属基复合材料性能提高及改善程度和在不同金属基复合材料中仍存在的增强相各种团聚、分散问题与金属基体的界面结合等及目前提出的处理方案,最后提出制备石墨烯金属基复合材料未来发展方向及新型制备技术仍存在的实际问题。     

表面活性剂辅助的水相剥离法制备石墨烯研究进展

表面活性剂辅助水相剥离法是一种制备较高质量石墨烯的方法。概述了表面活性剂辅助的水相剥离方法的技术优势,包括方法绿色环保、便于规模化、所得石墨烯质量高和产量大等特点。在此基础上,重点综述了近年来不同种类表面活性剂辅助水相剥离石墨烯的研究进展,其中离子型表面活性剂辅助剥离石墨烯,包括烷基阴离子表面活性剂辅助剥离石墨、胆盐类表面活性剂辅助剥离石墨、芘衍生物辅助剥离石墨、阳离子型表面活性剂辅助剥离石墨等;非离子性表面活性剂辅助剥离石墨,包括聚乙烯吡咯烷酮辅助剥离石墨、聚醚表面活性剂辅助剥离石墨、聚乙烯基咪唑类高分子辅助水相剥离石墨等。针对各种形式的表面活性剂辅助水相剥离石墨方法,分别从制备流程、表面活性剂物理化学性能、制得的石墨烯的结构与性能等方面进行了归纳与对比。最后展望了液相剥离制备石墨烯方法在未来的发展方向。     

激光增材技术制备金属基石墨烯复合材料

增材制造技术（3D打印）是先进制造技术的重要发展方向,已经应用到航空航天、汽车工业、生物医学等重要领域中。自2004年首次剥离出单层石墨烯后,石墨烯等二维晶体材料逐渐成为了复合材料领域的研究热点。其表现出的优良力学性能及导电导热性使其更加适用于增强相材料。石墨烯与金属合金复合,通过调整石墨烯增强相的含量和分布,有望大幅提高金属基体材料的力学强度、导电导热等性能,获得性能优异的结构功能一体化材料。激光增材制造技术和石墨烯纳米片高比表面积和各向异性的优点相结合,对石墨烯与金属粉末进一步加工混合,再逐层打印构造3D 结构,已成为一个全新的研究方向,正在引领着第四代工业革命的进展。本文以激光增材制造技术为主体,从三个角度综述激光增材制造技术制备金属基石墨烯复合材料的研究进展,即激光增材制造技术制备石墨烯铝、镍及其他金属基复合材料,对比了形成工艺以及材料的性能,并分析了今后可能的发展方向。     

石墨烯增强铜基复合材料的制备及研究现状

石墨烯由于具有优异的力学与功能内禀特性,成为金属基复合材料的理想增强相,近年来受到各国研究者的广泛关注。本文总结了石墨烯增强铜基复合材料的制备方法、改善石墨烯分散均匀性以提高其与铜基体界面结合性能的研究进展,最后对石墨烯增强铜基复合材料的应用及未来发展方向进行了展望。     

Graphene-Reinforced Metal and Polymer Matrix Composites

Composites have tremendous applicability due to their excellent capabilities. The performance of composites mainly depends on the reinforcing material applied. Graphene is successful as an efficient reinforcing material due to its versatile as well as superior properties. Even at very low content, graphene can dramatically improve the properties of polymer and metal matrix composites. This article reviews the fabrication followed by mechanical and tribological properties of metal and polymer matrix composites filled with different kinds of graphene, including single-layer, multilayer, and functionalized graphene. Results reported to date in literature indicate that functionalized graphene or graphene oxide-polymer composites are promising materials offering significantly improved strength and frictional properties. A similar trend of improved properties has been observed in case of graphene-metal matrix composites. However, achieving higher graphene loading with uniform dispersion in metal matrix composites remains a challenge. Although graphene-reinforced composites face some challenges, such as understanding the graphene-matrix interaction or fabrication techniques, graphene-reinforced polymer and metal matrix composites have great potential for application in various fields due to their outstanding properties.     

热处理对半固态注射成形石墨烯/镁基复合材料组织及性能的影响

研究了不同固溶温度和时效时间对半固态注射成形石墨烯增强镁基复合材料组织及性能的影响。结果表明,随着固溶温度升高,复合材料硬度(HV)逐渐减小,在200℃时复合材料硬度最高;β-Mg17Al12相含量先增大后减少,在400℃时几乎全部消失。随着时效时间增加,复合材料硬度(HV)先增加后减少,在时效12h时达到最大,为93.17。经过固溶处理和时效处理后石墨烯在复合材料基体中稳定存在,且对复合材料的硬度产生影响。     

Synthesis,characterization and optical studies on Sm~(2+)-doped CdSe nanocrystals:a blueshift and fixed emission with high quantum yields

CdSe:Sm nanocrystals(NCs) were synthesized by a water phase method,and their structures,shapes and optical properties were further characterized.X-ray diffraction(XRD) analysis suggested that both the CdSe and CdSe:Sm NCs contained(111),(220) and(311) lattice planes in the zinc blende structure overlapped with the(002),(110) and(112) lattice planes in the wurtzite structure,and the diameters were about 4.2,3.3 and 2.3 nm for CdSe,CdSe:Sm(8%) and CdSe:Sm(10%) NCs,respectively.All of the CdSe:Sm NCs were monodispersed and uniform spherical nanocrystals.The CdSe:Sm(10%) NCs prepared with different reaction times exhibited constant absorption spectra at 430 nm and a fixed emission peak at581 nm.Compared with those of pure CdSe NCs,the fluorescence emission of CdSe:Sm(10%) NCs blueshifted 20-36 nm,and the absorption peak initially redshifted and then blueshifted with the prolongation of reaction time.In addition,the Sm~(2+) doping decreased the fluorescence lifetime and increased the quantum yields(QYs) of CdSe NCs.The QYs of CdSe:Sm NCs increased initially and then decreased with the increase in the amount of doped Sm~(2+).The initial pH and charge compensator concentration also exhibited significantly enhanced fluorescence emission of CdSe:Sm NCs.     

W-Cu composites reinforced by copper coated graphene prepared using infiltration sintering and spark plasma sintering: A comparative study

In order to solve problems of significant interfacial reactions and agglomeration in graphene reinforced WCu composites, powders of copper coated graphene (Cu@Gr) were pre-mechanically mixed with tungsten and copper powders, and then graphene doped WCu composites were sintered using two different methods, e.g., spark plasma sintering (SPS) and infiltration sintering. Microstructural analysis showed that the doped Cu@Gr powder can effectively inhibit the interfacial reaction between graphene and tungsten, prevent the segregation of graphene, and evenly distribute the copper in the binder phase. When the mixed concentration of Cu@Gr was 0.45 wt%, uniform distributions of W phase and Cu phase were obtained in the composite, and the mechanical properties and conductivity of this composite achieved their best results. When the doping content was further increased to 0.8%, WC phase was found in all alloys, thus resulting in poor mechanical and physical properties. Comparing the microstructures produced using these two methods, the composites prepared using the infiltration sintering method showed network distribution of copper phase and segregation of copper, whereas the composites prepared using the SPS method showed network skeleton phase of tungsten. Although the SPS process was performed in a much shorter time, the mechanical properties of the composites sintered using the SPS process did not show much differences with those sintered using the infiltration sintering method.     

石墨烯增强铜基复合材料的制备技术及发展

石墨烯由于其独特的二维结构和优异的物化性能,在改善复合材料的力学性能、电学性能和热学性能等方面具有很大的潜力,已成为金属基复合材料较理想的增强体。铜合金具有优异的导电导热性能和良好的延展性,但是其强度较低、不耐磨及高温下易变形的特点阻碍了其应用和发展。因此,结合石墨烯和铜的性能特点,将石墨烯作为增强体添加到铜中,制备性能优异的石墨烯增强铜基复合材料成为目前研究的热点之一。综述了目前石墨烯增强铜基复合材料的制备方法,并对各方法的特点进行了分析比较,提出未来可采用的制备工艺的方向以及在制备过程中面临的问题和挑战,并对其未来的研究方向进行了展望。     

C_n团簇注入制备石墨烯的研究进展

石墨烯是碳原子构成的单层二维晶体,在高频电子学和光电子器件领域具有广泛应用前景,厚度可控的大面积石墨烯的制备是实现规模化应用的前提。文中在介绍现有石墨烯制备技术优缺点的基础上,重点介绍了近几年离子注入过渡金属镍制备石墨烯的研究成果。研究表明:在低能碳团簇C_n注入制备石墨烯的过程中,离子能量、注入剂量、团簇尺寸、基体材料特性和退火条件是影响石墨烯物理性质的重要因素。团簇离子注入在基体表层引起的辐照损伤具有非线性效应,精确控制剂量的C_n团簇注入到基体中主要起到提供可控掺杂碳源的作用,高质量石墨烯的合成需要进行多晶基体预热处理以减少晶界密度,同时需采取精细的后续热处理工艺,控制碳原子在基体表面横向扩散和偏析,以满足石墨烯形核生长的关键条件。     

石墨烯涂层刀具的研究现状

针对高效干式切削加工中润滑能力不足,将自润滑性能优良的石墨烯粒子原位生长或者以复合材料的形式沉积于硬质合金刀具基体表面,有望弥补传统干切削中刀具使用寿命和加工性能偏低的不足。介绍了石墨烯材料在金属切削刀具领域中的研究和应用的现状,解读使用不同的工艺制备方法获得原生石墨烯涂层或者石墨烯复合超硬材料,并用其进行金属切削加工和摩擦磨损的试验。结果表明：石墨烯涂层刀具具备优良的润滑性能,能有效降低刀具的摩擦因数和磨损率,提高其使用寿命。     

放电等离子烧结法制备石墨烯-铜铬锆合金的组织与性能

采用低能球磨和放电等离子烧结法制备了石墨烯(GNPs)增强铜基复合材料.研究了石墨烯含量对复合材料微观结构和性能的影响.结果 表明,随着石墨烯含量的增加,复合材料的力学性能呈现出先升高后降低的趋势.其中,当石墨烯含量为0.25％(质量分数)时,复合材料的极限抗压强度为409 MPa,合金的导电率高达90％ IACS.石...     

石墨烯增强铜基复合材料的研究进展

石墨烯由于独特的结构和优异的性能,成为复合材料中最具吸引力的碳质材料增强体。系统介绍了近年来石墨烯增强铜基复合材料的制备方法以及国内外相关研究现状。针对石墨烯表面润湿性和分散性差的问题,概述了石墨烯表面改性的方法及相关研究进展,提出了利用稀土对石墨烯进行表面改性的可行性。总结了目前石墨烯增强铜基复合材料研究中存在的主要问题,并对今后石墨烯增强铜基复合材料的研究方向及发展趋势进行了展望。     

石墨烯协同反应自生氧化铝增强铝硅基复合材料的研究

以铝、二氧化硅和石墨烯为原料,采用粉末冶金和原位反应相结合的方法制备石墨烯协同反应自生氧化铝增强Al-Si基复合材料,并对复合材料的物相、组织及性能进分析。结果表明:石墨烯及反应生成的氧化铝颗粒都较为均匀的分布在复合材料基体中起到增强作用;复合材料的致密度和硬度均在二氧化硅质量分数为25%时达到最大,分别为87.08%和77.54 HB,其硬度较未添入石墨烯的复合材料提升了10.3%.     

Cyclodextrin mediated phase transfer in water of organic capped CdS nanocrystals

In this work the phase transfer of blue emitting CdS nanocrystals (NCs) from organic solvent to water is reported. Oleic acid capped CdS NCs were synthesized in non-coordinating solvents and effectively transferred from organic phase, i.e. hexane, in aqueous solution. The transfer was mediated by the formation of an inclusion complex between NC surfactant and α-cyclodextrin (αCD). Effect of αCD concentration and NC size on the phase transfer process was evaluated. No NC aggregation in the phase transfer and long stability in time were observed. The spectroscopic properties of the resulting solution were investigated. Finally a supramolecular hierarchical multilayer system with high level of structural complexity was fabricated by using a layer-by-layer assembling procedure of CdS-NC/αCD inclusion complex in multilayered films.     

金属-石墨烯复合涂层研究进展

对石墨烯与各种材料的复合涂层进行了详细的介绍,主要包括金属-石墨烯复合涂层的制备方式、制备工艺、石墨烯的分散性以及石墨烯的添加对涂层性能的影响.电沉积、化学镀和电刷镀等制备方式都可以获得均匀致密的复合涂层,石墨烯的加入细化了涂层的晶粒,使涂层的微观形貌发生了一定的改变.石墨烯作为第二相粒子添加时,机械超声分散效果较差,一般通过添加表面活性剂再配合机械超声分散的方式来分散石墨烯,表面活性剂中的阴离子活性剂与阳离子活性剂配合使用分散效果较好.另外,还有一种保持石墨烯在溶液中浓度动态平衡的方法也有较好的效果.石墨烯作为第二相粒子加入金属涂层中,增强了金属涂层的导热、导电、耐磨、硬度和耐腐蚀等方面性能.最后,分析展望了金属与石墨烯复合涂层的发展趋势.     

单晶金属衬底上多层石墨烯的可控生长进展

石墨烯作为一种理想的二维材料,具有机械性能好、电阻率低、热导率高等优点,受到人们的广泛关注。特别地,通过调控石墨烯层数可以改变石墨烯的电学性质,如带隙可调、半导体性质、特殊量子行为等,拓展石墨烯在柔性透明电极、高温超导、高性能传感等领域的应用。目前,人们已对金属衬底上高质量单层石墨烯的制备做了很多研究,发现当单层石墨烯覆盖金属衬底时,衬底将失去催化活性,使得高质量多层石墨烯的可控生长变得非常困难。为了制备多层石墨烯,研究人员已经探索了多种生长方法。总结了单晶金属衬底上多层石墨烯两种常见的生长模式,即表面成核控制的层层往上生长和偏析成核控制的层层往下生长,表面成核控制生长包括气源分子束外延、等离子体化学气相沉积等,偏析成核控制生长包括合金衬底偏析、单质金属衬底偏析等。针对多层石墨烯的各种生长方法,分别从成核密度、晶畴尺寸、层厚均匀性等方面进行了分析总结。最后,对该领域的发展趋势进行了展望,有助于为多层石墨烯的可控生长提供新的解决方案,促进多层石墨烯的发展与应用。     

耐腐蚀氧化石墨烯复合涂层的研究进展

腐蚀问题会影响金属材料的安全性和耐久性,是造成工程装备和设施失效及破坏的主要原因,严重损害了经济发展和人身安全。涂层是最有效和经济的防腐措施,随着对涂层性能的要求越来越高,复合涂层材料受到科研工作者的广泛关注。石墨烯具有高导电率、高硬度和优异的阻隔性等性能,但同时具有疏水性和易团聚的特点。氧化石墨烯的结构与石墨烯相似,高长径比能够提供有效的阻隔性能,表面丰富的含氧基团为化学改性提供了反应位点,从而实现在基体中均匀分散的目的,是一种可用于增强涂层防腐能力的理想碳材料。首先介绍了氧化石墨烯的制备和化学改性方法,并且对比了不同化学改性方法的优缺点以及作用机制。然后分类阐述了氧化石墨烯复合防腐涂层的研究现状,探讨了氧化石墨烯含量、分散性和制备条件等因素对复合涂层的影响。最后从不同方面(制备工艺、分散技术、防腐机制和工程应用)分析了氧化石墨烯涂层存在的主要问题,并展望了氧化石墨烯涂层的发展方向。     

A novel approach to composite preparation by direct synthesis of carbon nanomaterial on matrix or filler particles

Carbon nanotubes (CNTs), nanofibers (CNFs) and graphene are promising components for next-generation high-performance structural and multifunctional composite materials. One of the largest obstacles to creating strong, electrically or thermally conductive CNT/CNF or graphene composites is the difficulty of achieving a good dispersion of the carbon nanomaterials in a matrix. Typically, time-consuming steps of carbon nanomaterial purification, ultrasound treatment and functionalization are required. We utilized a novel approach to fabricate composite materials by growing CNTs/CNFs directly on the surface of matrix, matrix precursor or filler particles. As the precursor matrix and fillers we utilized cement (clinker), copper powder, fly ash particles, calcinated soil and sand. Carbon nanomaterials were successfully grown on these materials without additional catalyst. Investigations of the physical properties of the composite materials based on these carbon-modified particles revealed enhanced mechanical and electrical properties. The improvement in the mechanical properties of the C/Cu-based composite materials is attributed the crystallite or grain formation of the matrix material.     

Fabrication and characterization of graphene-reinforced waterborne polyurethane nanocomposite coatings by the sol–gel method

Functionalized graphene-reinforced polyurethane nanocomposite coatings were prepared using the sol–gel method. This method not only provides a “green” strategy for fabricating the graphene-based nanocomposites, but also realizes the covalent functionalization of graphene nanosheets with polymer matrix. The functionalization of graphene with conjugated organosilanes is favorable for improving mechanical and thermal properties of the nanocomposite coatings, which is mainly attributed to the homogeneous dispersion of functionalized graphene in the polymer matrix and strong interfacial interactions between the two components. A 71% increase in tensile strength and a 86% improvement of Young's modulus are observed by the addition of 2.0 wt.% of functionalized graphene. The experimentally determined Young's modulus corresponds well with the theoretical simulation under the hypothesis that the graphene sheets are randomly dispersed in the polymer matrix.