碳纳米管增强陶瓷材料机理研究现状

碳纳米管作为一维纳米材料,不仅重量轻,还具有强度高、韧性高等优异的力学性能,与工程结构陶瓷材料复合能够强韧化陶瓷材料的力学性能,被认为是现代结构陶瓷复合材料的理想增强体。在综合了近年碳纳米管增强陶瓷基复合材料的理论及实验方面研究结果的基础上,侧重介绍了碳纳米管增强陶瓷基复合材料的强韧化机理,如细化晶粒增韧、短纤维增韧、碳纳米管独特的坍塌增韧、多壁碳纳米管抽出增韧机制,并讨论了采用剪切滞后理论模型对碳纳米管与陶瓷基体的微观界面结合力学性能模拟的研究结果。分析了国内外碳纳米管在陶瓷基体中强韧化机理的实验及模拟研究结果,总结了当前碳纳米管增强陶瓷复合材料的研究困境与存在的问题,并指出了今后理论和实验研究的方向。     

碳纳米管增强铝基复合材料分散方法研究进展

碳纳米管与铝基体的结合,可以获得导电和导热性良好及综合力学性能优异的复合材料,有望成为新一代轻质高强、结构功能一体化的复合材料.在制备碳纳米管增强铝基复合材料过程中,碳纳米管的团聚将降低界面结合,诱发缺陷产生,导致性能大幅下降,因此,调控优化碳纳米管的分散状态、含量成为获取良好界面结合,获得高性能碳纳米管增强铝基复合材...     

碳纳米管/陶瓷基复合材料研究进展

介绍了碳纳米管的结构、制备、处理及性能,综述了碳纳米管/陶瓷基复合材料的制备方法以及碳纳米管/陶瓷基功能复合材料的研究进展,并对复合材料制备中碳纳米管的分散、取向与阵列、烧损和复合材料的界面等问题进行了分析.     

碳纳米管增强镁基复合材料的研究现状及发展

综述了碳纳米管增强镁基复合材料的最新研究进展,介绍了国内外在该领域研究的主要制备方法,并对各种制备方法的优缺点进行了分析.阐述了目前碳纳米管增强镁基复合材料领域所面临的主要问题:如何使碳纳米管均匀分散在基体中;如何使碳纳米管与镁基体界面结合良好.讨论了碳纳米管增强镁基复合材料的主要动向,并展望了今后的发展.     

碳纳米管在铝基复合材料中分散的研究进展

由于具有独特的结构和优异的性能,碳纳米管(CNTs)被认为是铝基复合材料的理想增强相。CNTs的增强效果很大程度上取决于其在铝基体中分散的均匀性,但CNTs却很难分散,给高性能CNTs/Al复合材料的制备带来了不小的难题。简要分析了CNTs在铝基体中分散困难的原因以及分散性对复合材料性能的影响,详细介绍了球磨、纳米尺度分散、分子级别混合、原位合成、喷雾干燥等主要的CNTs在铝基体中的分散方法。最后,讨论了关于CNTs分散程度的量化评估方法。     

碳纳米管增强环氧树脂复合材料阻尼性能的研究

采用热压成型法制备出碳纳米管环氧树脂复合材料,并对其分散性能和阻尼性能进行了研究。扫描电镜(SEM)分析表明,通过超声振荡处理和分散剂辅助处理可以将碳纳米管较好地分散在环氧树脂基体材料中。采用自由振动对数衰减率法和动态热机械分析仪(DMTAⅤ)对复合材料的阻尼性能进行了测试,结果表明,在环氧树脂基体中加入碳纳米管能够提高复合材料的阻尼性能,并且随着碳纳米管质量分数的增加,复合材料的阻尼性能不断增强,掺加直径为10~20nm的碳纳米管比掺加直径为30~50nm的碳纳米管能更大地提高复合材料的阻尼性能。     

碳纳米管增强环氧树脂基复合材料研究进展及建议

碳纳米管与环氧树脂复合得到的复合材料是具有广阔应用前景的新型材料。介绍了碳纳米管的分散及碳纳米管增强环氧树脂基复合材料的主要制备方法;着重论述了碳纳米管增强环氧树脂基复合材料的性能,以及这些方法制备出的复合材料存在的主要问题和解决方向。指出随着研究的不断深入,碳纳米管增强环氧树脂基复合材料的应用会逐渐广阔。     

搅拌摩擦加工法制备碳纳米管增强铝基复合材料

为了制备晶粒细小、 组织均匀的复合材料, 提高材料的力学性能, 用搅拌摩擦加工法制备碳纳米管增强铝基复合材料, 并对不同碳纳米管含量的复合材料的微观结构、 拉伸性能及断口形貌进行分析。结果表明: 碳纳米管添加到铝基体中, 搅拌摩擦中心区晶粒细小, 碳纳米管与基体之间结合良好, 未发现明显的缺陷; 碳纳米管对基材有明显的强化作用, 铝基复合材料抗拉强度随着碳纳米管含量的增加而提高; 碳纳米管体积分数为7%时, 抗拉强度达到201 MPa, 是基材的2.2倍; 复合材料在宏观上呈现脆性断裂特征, 微观上呈现韧性断裂特征, 其断裂机制以CNTs/Al界面脱粘、 基体撕裂和增强体断裂为主。      

碳纳米管水泥基复合材料的性能探讨

碳纳米管自从被发现以来,以其优异的性能在物理、化学和材料等研究领域引起广泛关注。针对近年来国内外学者对碳纳米管增强水泥基材料物理力学性能进行的相关研究,介绍了碳纳米管在水泥基体中的分散性及其增强复合材料存在的问题,详细阐述了碳纳米管水泥基复合材料的力学性能、耐久性、导电性和自感知性以及吸波性能,为水泥基复合材料的功能性研究和应用提供了借鉴。     

碳纳米管增强2024铝基复合材料的力学性能及断裂特性

为了研究碳纳米管对铝基复合材料性能的影响,采用冷等静压、热挤压方法制备了质量分数1.0%的多壁碳纳米管增强2024Al基复合材料.采用扫描电镜、透射电镜和拉伸试验对复合材料的显微组织进行了观察和分析,并对其力学性能进行了测试.结果表明,碳纳米管均匀地分布在复合材料中,碳纳米管和铝基体的界面结合良好,没有发现界面产物Al4C3的形成;复合材料的断口上存在大量的撕裂棱,韧窝,并涉及碳纳米管的拔出或拔断与桥接,与2024Al基体材料相比,复合材料的硬度、弹性模量和抗拉强度显著提高,同时复合材料的延伸率却并不下降.碳纳米管的加入可以显著提高铝基复合材料的力学性能.     

碳纳米管增强金属基复合材料电学性能研究进展

碳纳米管(CNTs)具有极高的力学性能、优异的导电和导热性能,被视为理想的复合材料增强相。CNTs增强复合材料已成为一个极为重要的研究领域。然而,由于CNTs与金属基体间相容性、增强体空间分布难以控制、CNTs本身载流量高而电导率相对较低等,CNTs增强金属基复合材料尚未展现出对金属基体电学性能的显著提升,或者无法有效兼顾电学性能和力学性能,整体研究仍处于起步阶段。鉴于此,从预处理、制备方法和电学机制分析等方面概述了CNTs增强金属基复合材料电学性能的研究现状,并展望了该领域的未来发展趋势。      

Recent advances in understanding the reinforcing ability and mechanism of carbon nanotubes in ceramic matrix composites

Since the discovery of carbon nanotubes (CNTs), commonly referred to as ultimate reinforcement, the main purpose for fabricating CNT–ceramic matrix composites has been mainly to improve the fracture toughness and strength of the ceramic matrix materials. However, there have been many studies reporting marginal improvements or even the degradation of mechanical properties. On the other hand, those studies claiming noticeable toughening measured using indentation, which is an indirect/unreliable characterization method, have not demonstrated the responsible mechanisms applicable to the nanoscale, flexible CNTs; instead, those studies proposed those classical methods applicable to microscale fiber/whisker reinforced ceramics without showing any convincing evidence of load transfer to the CNTs. Therefore, the ability of CNTs to directly improve the macroscopic mechanical properties of structural ceramics has been strongly questioned and debated in the last ten years. In order to properly discuss the reinforcing ability (and possible mechanisms) of CNTs in a ceramic host material, there are three fundamental questions to our knowledge at both the nanoscale and macroscale levels that need to be addressed: (1) does the intrinsic load-bearing ability of CNTs change when embedded in a ceramic host matrix?; (2) when there is an intimate atomic-level interface without any chemical reaction with the matrix, could one expect any load transfer to the CNTs along with effective load bearing by them during crack propagation?; and (3) considering their nanometer-scale dimensions, flexibility and radial softness, are the CNTs able to improve the mechanical properties of the host ceramic matrix at the macroscale when individually, intimately and uniformly dispersed? If so, how? Also, what is the effect of CNT concentration in such a defect-free composite system? Here, we briefly review the recent studies addressing the above fundamental questions. In particular, we discuss the new reinforcing mechanism at the nanoscale responsible for unprecedented, simultaneous mechanical improvements and highlight the scalable processing method enabling the fabrication of defect-free CNT-concentered ceramics and CNT-graded composites with unprecedented properties. Finally, possible future directions will be briefly presented.     

碳纳米管增强镁基复合材料导热性能研究

镁及其合金是目前最轻的金属结构材料,合金化虽然提升了镁合金的力学性能,但导致其导热性能严重下降,限制了镁合金的应用。碳纳米管(CNTs)因具有优异的力学、热学等性能,是最理想的增强体之一,可以用于改善镁合金的力学性能和热学性能。采用粉末冶金法分别以纯Mg、Mg-9Al合金、Mg-6Zn合金为基体制备了不同CNTs含量的镁基复合材料,利用光学显微镜、扫描电子显微镜、透射电子显微镜对复合材料微观组织、基体与增强体界面及析出相进行表征,并对复合材料的拉伸性能和热学性能进行测试。研究结果表明,当CNTs质量分数不超过1.0%时,可提高纯镁基复合材料的导热性能,力学性能仅有稍微降低;将CNTs添加到Mg-9Al合金中,可以促进纳米尺度β-Mg 17 Al 12相在CNTs周围析出,降低了Al在Mg基体中的固溶度,使CNTs/Mg-9Al复合材料的导热性能有所提高。此外,在CNTs/Mg-6Zn复合材料界面处存在C原子和Mg原子的相互嵌入区,这种嵌入型界面不仅有利于复合材料力学性能的提高,也使CNTs起到加速电子移动的“桥”的作用,有利于该复合材料热导率的提高。当CNTs质量分数为0.6%时,CNTs/Mg-6Zn复合材料具有较为优异的热学性能和力学性能,其热导率为127.0 W/(m·K),抗拉强度为303.0 MPa,屈服强度为204.0 MPa,伸长率为5.0%。     

碳纳米管表面处理及其在铜基复合材料中的应用

碳纳米管因特殊结构带来的优异性能而被海内外学者广泛关注,以碳纳米管为增强相制备铜基复合材料是使铜基导体同时具有高强度和高导电性能的有效途径。然而,由于碳纳米管表面能高、表面反应活性低,碳纳米管/铜复合材料制备的过程中存在增强体分散性差和界面结合强度弱两大问题,从而阻碍了复合材料高性能的实现。在碳纳米管/铜复合材料的制备过程中,采用适当的方法对碳纳米管进行表面处理能改变碳纳米管的表面结构和反应活性,在改善碳纳米管的分散性的同时增强碳纳米管与铜基体的界面结合,从而提高碳纳米管的增强效率,保证复合材料良好的综合性能。然而,表面处理过程可能会破坏碳纳米管的结构完整性,影响碳纳米管的本征性能,进而影响其增强效果,或可能在基体中引入其他杂质,影响复合材料的导电和导热性能。因此,在进行表面处理时应综合考虑其对碳纳米管结构性能及复合材料增强作用的影响。近年来,研究者们通过优化碳纳米管表面处理工艺突破了碳纳米管/铜复合材料在制备过程的难点,在保证铜基体优异的导电、导热性能的同时,大幅提高了碳纳米管/铜复合材料的力学性能。碳纳米管表面处理工艺类型大致可分为机械球磨、化学表面改性、表面镀层和联合表面处理四类。传统的机械球磨表面处理对碳纳米管的结构破坏较大;化学表面改性又分为共价表面改性和非共价表面改性,非共价表面改性在保持碳纳米管完整的管状结构和优异性能的同时,提高了碳纳米管在溶液中的分散性,但用于复合材料制备时会给基体引入有机杂质,影响复合材料性能;共价表面改性和表面镀层是铜基复合材料制备过程中最为常用和有效的表面处理方法,其能够在提高碳纳米管在基体中的分散性能的同时改善碳纳米管表面的反应活性,从而形成碳纳米管和铜基体之间强度较高的反应结合界面,实现碳纳米管/铜复合材料高强高导的综合性能。此外,可通过综合利用各种表面处理方法,结合各表面处理工艺的优势,获得更为优异的改性效果。本文从碳纳米管表面处理工艺的基本类型以及碳纳米管表面处理对铜基复合材料结构和性能的影响两方面阐述了碳纳米管表面处理在铜基复合材料中的应用和研究进展,并对其未来的研究方向进行了展望。     

碳纳米管/丁苯橡胶复合材料的电学性能

采用喷雾干燥法可制备不同配比的碳纳米管（Carbon nanotubes,CNTs）/粉末丁苯橡胶复合材料,观察CNTs在橡胶基体中的分散情况,检测复合材料的导电性能及介电性能,并进行了简要的理论分析。结果表明:CNTs在橡胶基体中获得了充分均匀的分散,有利于CNTs改性补强作用的发挥。与纯胶样品及填充炭黑（Carbon black,CB）样品相比, 填充CNTs样品在8~18GHz下具有较高的介电常数及低介电损耗。随着CNTs加入量的增加,CNTs/粉末丁苯橡胶复合材料的电导率逐渐升高,当CNTs加入量为60phr（per hundred rubber）时,与纯胶样品及添加60phr CB样品相比,电导率提高近10个数量级;复合材料内部导电同时存在隧道导电机制和渗逾导电机制。采用喷雾干燥法制备的CNTs/粉末丁苯橡胶复合材料,将是一种综合性能良好的新型纳米复合材料,有望在抗静电橡胶、电磁屏蔽及介电材料等领域获得应用。      

Ceramic matrix composites containing carbon nanotubes

Due to the remarkable physical and mechanical properties of individual, perfect carbon nanotubes (CNTs), they are considered to be one of the most promising new reinforcements for structural composites. Their impressive electrical and thermal properties also suggest opportunities for multifunctional applications. In the context of inorganic matrix composites, researchers have particularly focussed on CNTs as toughening elements to overcome the intrinsic brittleness of the ceramic or glass material. Although there are now a number of studies published in the literature, these inorganic systems have received much less attention than CNT/polymer matrix composites. This paper reviews the current status of the research and development of CNT-loaded ceramic matrix composite (CMC) materials. It includes a summary of the key issues related to the optimisation of CNT-based composites, with particular reference to brittle matrices and provides an overview of the processing techniques developed to optimise dispersion quality, interfaces, and density. The properties of the various composite systems are discussed, with an emphasis on toughness; a comprehensive comparative summary is provided, together with a discussion of the possible toughening mechanism that may operate. Last, a range of potential applications are discussed, concluding with a discussion of the scope for future developments in the field.     

AlN-CNTs/聚酰亚胺复合材料的制备与性能

为了研究氮化铝(AlN)和碳纳米管(CNTs)对聚酰亚胺(PI)的导热、热学、力学性能的协同效应,采用湿法球磨和热压成型法制备了AlN/PI和CNTs-AlN/PI复合材料。利用X射线衍射仪、扫描电子显微镜对复合材料进行了物相分析和断面形貌表征,分别考察了AlN及其与CNTs协同对PI复合材料的导热、热学、力学性能的影响。结果表明,AlN和CNTs在PI基体中分散均匀且接触界面良好,AlN的加入可以显著地提高复合材料的导热性能,且对复合材料的热稳定性和力学性能有一定的提高;固定AlN的含量为10%,加入少量的CNTs可以提高复合材料的导热性能,但对复合材料的力学性能有一定的负面影响。     

纳米碳管增强炭/炭复合材料的研究进展

纳米碳管(CNTs)具有独特的结构、优异的力学性能、热稳定性与传导性能,是炭/炭(C/C)复合材料理想的增强体.综述了纳米碳管增强炭/炭(CNTs/C/C)复合材料的制备方法,讨论了该复合材料的微观结构、摩擦学性能和传导性能,并展望了CNTs/C/C复合材料的潜在应用和发展趋势.     

Effect of size and shape of metal particles to improve hardness and electrical properties of carbon nanotube reinforced copper and copper alloy composites

Utilizing the extra-ordinary properties of carbon nanotube (CNT) in metal matrix composite (MMC) for macroscopic applications is still a big challenge for science and technology. Very few successful attempts have been made for commercial applications due to the difficulties incorporating CNTs in metals with up-scalable processes. CNT reinforced copper and copper alloy (bronze) composites have been fabricated by well-established hot-press sintering method of powder metallurgy. The parameters of CNT–metal powder mixing and hot-press sintering have been optimized and the matrix materials of the mixed powders and composites have been evaluated. However, the effect of shape and size of metal particles as well as selection of carbon nanotubes has significant influence on the mechanical and electrical properties of the composites. The hardness of copper matrix composite has improved up to 47% compared to that of pure copper, while the electrical conductivity of bronze composite has improved up to 20% compared to that of the pure alloy. Thus carbon nanotube can improve the mechanical properties of highly-conductive low-strength copper metals, whereas in low-conductivity high-strength copper alloys the electrical conductivity can be improved.     

Preparation and properties of powder styrene-butadiene rubber composites filled with carbon black and carbon nanotubes

Carbon nanotubes (CNTs) and carbon black (CB) filled powder styrene-butadiene rubber (SBR) composites were prepared by spray drying of the suspension of CNTs and CB in SBR latex. The powders were sphere like and fine with uniform diameters of 10-15 μm. Experimental results showed that the introduction of CNTs into the matrix was beneficial to improve the security of the vulcanization of the rubber composites, and the dynamic and basic mechanical properties of the CNTs/SBR composites were better than those of CB/SBR and neat SBR composites. Observations on the microstructure of the composites indicated that CNTs were well dispersed in the matrix. Morphology of the fracture confirmed that the bonding between CNTs and rubber matrix was strong and load can be transferred to CNTs efficiently during the mechanical property tests. Moreover, the powder SBR composites containing well-dispersed CNTs could be perfect candidate as additives for other polymers.